29 files changed, 872 insertions, 578 deletions

diff --git a/lib/Kconfig b/lib/Kconfig
index 986ea474836c..dc1ab2ed1dc6 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -118,6 +118,13 @@ config INDIRECT_IOMEM_FALLBACK
 	  mmio accesses when the IO memory address is not a registered
 	  emulated region.
 
+config TRACE_MMIO_ACCESS
+	bool "Register read/write tracing"
+	depends on TRACING && ARCH_HAVE_TRACE_MMIO_ACCESS
+	help
+	  Create tracepoints for MMIO read/write operations. These trace events
+	  can be used for logging all MMIO read/write operations.
+
 source "lib/crypto/Kconfig"
 
 config LIB_MEMNEQ
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 04aaa20d50f9..072e4b289c13 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -498,7 +498,7 @@ config STACK_VALIDATION
 	  runtime stack traces are more reliable.
 
 	  For more information, see
-	  tools/objtool/Documentation/stack-validation.txt.
+	  tools/objtool/Documentation/objtool.txt.
 
 config NOINSTR_VALIDATION
 	bool
@@ -699,6 +699,14 @@ config DEBUG_OBJECTS_ENABLE_DEFAULT
 	help
 	  Debug objects boot parameter default value
 
+config SHRINKER_DEBUG
+	bool "Enable shrinker debugging support"
+	depends on DEBUG_FS
+	help
+	  Say Y to enable the shrinker debugfs interface which provides
+	  visibility into the kernel memory shrinkers subsystem.
+	  Disable it to avoid an extra memory footprint.
+
 config HAVE_DEBUG_KMEMLEAK
 	bool
 
@@ -1560,7 +1568,7 @@ config DEBUG_KOBJECT_RELEASE
 	help
 	  kobjects are reference counted objects.  This means that their
 	  last reference count put is not predictable, and the kobject can
-	  live on past the point at which a driver decides to drop it's
+	  live on past the point at which a driver decides to drop its
 	  initial reference to the kobject gained on allocation.  An
 	  example of this would be a struct device which has just been
 	  unregistered.
diff --git a/lib/Kconfig.ubsan b/lib/Kconfig.ubsan
index a9f7eb047768..fd15230a703b 100644
--- a/lib/Kconfig.ubsan
+++ b/lib/Kconfig.ubsan
@@ -84,6 +84,9 @@ config UBSAN_SHIFT
 config UBSAN_DIV_ZERO
 	bool "Perform checking for integer divide-by-zero"
 	depends on $(cc-option,-fsanitize=integer-divide-by-zero)
+	# https://github.com/ClangBuiltLinux/linux/issues/1657
+	# https://github.com/llvm/llvm-project/issues/56289
+	depends on !CC_IS_CLANG
 	help
 	  This option enables -fsanitize=integer-divide-by-zero which checks
 	  for integer division by zero. This is effectively redundant with the
diff --git a/lib/Makefile b/lib/Makefile
index de3e47453fe8..17e48da223e2 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -29,7 +29,7 @@ endif
 
 lib-y := ctype.o string.o vsprintf.o cmdline.o \
 	 rbtree.o radix-tree.o timerqueue.o xarray.o \
-	 idr.o extable.o sha1.o irq_regs.o argv_split.o \
+	 idr.o extable.o irq_regs.o argv_split.o \
 	 flex_proportions.o ratelimit.o show_mem.o \
 	 is_single_threaded.o plist.o decompress.o kobject_uevent.o \
 	 earlycpio.o seq_buf.o siphash.o dec_and_lock.o \
@@ -45,7 +45,7 @@ obj-y += bcd.o sort.o parser.o debug_locks.o random32.o \
 	 bust_spinlocks.o kasprintf.o bitmap.o scatterlist.o \
 	 list_sort.o uuid.o iov_iter.o clz_ctz.o \
 	 bsearch.o find_bit.o llist.o memweight.o kfifo.o \
-	 percpu-refcount.o rhashtable.o \
+	 percpu-refcount.o rhashtable.o base64.o \
 	 once.o refcount.o usercopy.o errseq.o bucket_locks.o \
 	 generic-radix-tree.o
 obj-$(CONFIG_STRING_SELFTEST) += test_string.o
@@ -151,6 +151,8 @@ lib-y += logic_pio.o
 
 lib-$(CONFIG_INDIRECT_IOMEM) += logic_iomem.o
 
+obj-$(CONFIG_TRACE_MMIO_ACCESS) += trace_readwrite.o
+
 obj-$(CONFIG_GENERIC_HWEIGHT) += hweight.o
 
 obj-$(CONFIG_BTREE) += btree.o
diff --git a/lib/base64.c b/lib/base64.c
new file mode 100644
index 000000000000..b736a7a431c5
--- /dev/null
+++ b/lib/base64.c
@@ -0,0 +1,103 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * base64.c - RFC4648-compliant base64 encoding
+ *
+ * Copyright (c) 2020 Hannes Reinecke, SUSE
+ *
+ * Based on the base64url routines from fs/crypto/fname.c
+ * (which are using the URL-safe base64 encoding),
+ * modified to use the standard coding table from RFC4648 section 4.
+ */
+
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/export.h>
+#include <linux/string.h>
+#include <linux/base64.h>
+
+static const char base64_table[65] =
+	"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+
+/**
+ * base64_encode() - base64-encode some binary data
+ * @src: the binary data to encode
+ * @srclen: the length of @src in bytes
+ * @dst: (output) the base64-encoded string.  Not NUL-terminated.
+ *
+ * Encodes data using base64 encoding, i.e. the "Base 64 Encoding" specified
+ * by RFC 4648, including the  '='-padding.
+ *
+ * Return: the length of the resulting base64-encoded string in bytes.
+ */
+int base64_encode(const u8 *src, int srclen, char *dst)
+{
+	u32 ac = 0;
+	int bits = 0;
+	int i;
+	char *cp = dst;
+
+	for (i = 0; i < srclen; i++) {
+		ac = (ac << 8) | src[i];
+		bits += 8;
+		do {
+			bits -= 6;
+			*cp++ = base64_table[(ac >> bits) & 0x3f];
+		} while (bits >= 6);
+	}
+	if (bits) {
+		*cp++ = base64_table[(ac << (6 - bits)) & 0x3f];
+		bits -= 6;
+	}
+	while (bits < 0) {
+		*cp++ = '=';
+		bits += 2;
+	}
+	return cp - dst;
+}
+EXPORT_SYMBOL_GPL(base64_encode);
+
+/**
+ * base64_decode() - base64-decode a string
+ * @src: the string to decode.  Doesn't need to be NUL-terminated.
+ * @srclen: the length of @src in bytes
+ * @dst: (output) the decoded binary data
+ *
+ * Decodes a string using base64 encoding, i.e. the "Base 64 Encoding"
+ * specified by RFC 4648, including the  '='-padding.
+ *
+ * This implementation hasn't been optimized for performance.
+ *
+ * Return: the length of the resulting decoded binary data in bytes,
+ *	   or -1 if the string isn't a valid base64 string.
+ */
+int base64_decode(const char *src, int srclen, u8 *dst)
+{
+	u32 ac = 0;
+	int bits = 0;
+	int i;
+	u8 *bp = dst;
+
+	for (i = 0; i < srclen; i++) {
+		const char *p = strchr(base64_table, src[i]);
+
+		if (src[i] == '=') {
+			ac = (ac << 6);
+			bits += 6;
+			if (bits >= 8)
+				bits -= 8;
+			continue;
+		}
+		if (p == NULL || src[i] == 0)
+			return -1;
+		ac = (ac << 6) | (p - base64_table);
+		bits += 6;
+		if (bits >= 8) {
+			bits -= 8;
+			*bp++ = (u8)(ac >> bits);
+		}
+	}
+	if (ac & ((1 << bits) - 1))
+		return -1;
+	return bp - dst;
+}
+EXPORT_SYMBOL_GPL(base64_decode);
diff --git a/lib/crypto/Kconfig b/lib/crypto/Kconfig
index 2082af43d51f..9ff549f63540 100644
--- a/lib/crypto/Kconfig
+++ b/lib/crypto/Kconfig
@@ -121,6 +121,9 @@ config CRYPTO_LIB_CHACHA20POLY1305
 	select CRYPTO_LIB_POLY1305
 	select CRYPTO_ALGAPI
 
+config CRYPTO_LIB_SHA1
+	tristate
+
 config CRYPTO_LIB_SHA256
 	tristate
 
diff --git a/lib/crypto/Makefile b/lib/crypto/Makefile
index 26be2bbe09c5..919cbb2c220d 100644
--- a/lib/crypto/Makefile
+++ b/lib/crypto/Makefile
@@ -34,6 +34,9 @@ libpoly1305-y					:= poly1305-donna32.o
 libpoly1305-$(CONFIG_ARCH_SUPPORTS_INT128)	:= poly1305-donna64.o
 libpoly1305-y					+= poly1305.o
 
+obj-$(CONFIG_CRYPTO_LIB_SHA1)			+= libsha1.o
+libsha1-y					:= sha1.o
+
 obj-$(CONFIG_CRYPTO_LIB_SHA256)			+= libsha256.o
 libsha256-y					:= sha256.o
 
diff --git a/lib/crypto/blake2s-selftest.c b/lib/crypto/blake2s-selftest.c
index 409e4b728770..7d77dea15587 100644
--- a/lib/crypto/blake2s-selftest.c
+++ b/lib/crypto/blake2s-selftest.c
@@ -4,6 +4,8 @@
  */
 
 #include <crypto/internal/blake2s.h>
+#include <linux/kernel.h>
+#include <linux/random.h>
 #include <linux/string.h>
 
 /*
@@ -587,5 +589,44 @@ bool __init blake2s_selftest(void)
 		}
 	}
 
+	for (i = 0; i < 32; ++i) {
+		enum { TEST_ALIGNMENT = 16 };
+		u8 unaligned_block[BLAKE2S_BLOCK_SIZE + TEST_ALIGNMENT - 1]
+					__aligned(TEST_ALIGNMENT);
+		u8 blocks[BLAKE2S_BLOCK_SIZE * 2];
+		struct blake2s_state state1, state2;
+
+		get_random_bytes(blocks, sizeof(blocks));
+		get_random_bytes(&state, sizeof(state));
+
+#if defined(CONFIG_CRYPTO_LIB_BLAKE2S_GENERIC) && \
+    defined(CONFIG_CRYPTO_ARCH_HAVE_LIB_BLAKE2S)
+		memcpy(&state1, &state, sizeof(state1));
+		memcpy(&state2, &state, sizeof(state2));
+		blake2s_compress(&state1, blocks, 2, BLAKE2S_BLOCK_SIZE);
+		blake2s_compress_generic(&state2, blocks, 2, BLAKE2S_BLOCK_SIZE);
+		if (memcmp(&state1, &state2, sizeof(state1))) {
+			pr_err("blake2s random compress self-test %d: FAIL\n",
+			       i + 1);
+			success = false;
+		}
+#endif
+
+		memcpy(&state1, &state, sizeof(state1));
+		blake2s_compress(&state1, blocks, 1, BLAKE2S_BLOCK_SIZE);
+		for (l = 1; l < TEST_ALIGNMENT; ++l) {
+			memcpy(unaligned_block + l, blocks,
+			       BLAKE2S_BLOCK_SIZE);
+			memcpy(&state2, &state, sizeof(state2));
+			blake2s_compress(&state2, unaligned_block + l, 1,
+					 BLAKE2S_BLOCK_SIZE);
+			if (memcmp(&state1, &state2, sizeof(state1))) {
+				pr_err("blake2s random compress align %d self-test %d: FAIL\n",
+				       l, i + 1);
+				success = false;
+			}
+		}
+	}
+
 	return success;
 }
diff --git a/lib/crypto/blake2s.c b/lib/crypto/blake2s.c
index c71c09621c09..98e688c6d891 100644
--- a/lib/crypto/blake2s.c
+++ b/lib/crypto/blake2s.c
@@ -16,16 +16,44 @@
 #include <linux/init.h>
 #include <linux/bug.h>
 
+static inline void blake2s_set_lastblock(struct blake2s_state *state)
+{
+	state->f[0] = -1;
+}
+
 void blake2s_update(struct blake2s_state *state, const u8 *in, size_t inlen)
 {
-	__blake2s_update(state, in, inlen, false);
+	const size_t fill = BLAKE2S_BLOCK_SIZE - state->buflen;
+
+	if (unlikely(!inlen))
+		return;
+	if (inlen > fill) {
+		memcpy(state->buf + state->buflen, in, fill);
+		blake2s_compress(state, state->buf, 1, BLAKE2S_BLOCK_SIZE);
+		state->buflen = 0;
+		in += fill;
+		inlen -= fill;
+	}
+	if (inlen > BLAKE2S_BLOCK_SIZE) {
+		const size_t nblocks = DIV_ROUND_UP(inlen, BLAKE2S_BLOCK_SIZE);
+		blake2s_compress(state, in, nblocks - 1, BLAKE2S_BLOCK_SIZE);
+		in += BLAKE2S_BLOCK_SIZE * (nblocks - 1);
+		inlen -= BLAKE2S_BLOCK_SIZE * (nblocks - 1);
+	}
+	memcpy(state->buf + state->buflen, in, inlen);
+	state->buflen += inlen;
 }
 EXPORT_SYMBOL(blake2s_update);
 
 void blake2s_final(struct blake2s_state *state, u8 *out)
 {
 	WARN_ON(IS_ENABLED(DEBUG) && !out);
-	__blake2s_final(state, out, false);
+	blake2s_set_lastblock(state);
+	memset(state->buf + state->buflen, 0,
+	       BLAKE2S_BLOCK_SIZE - state->buflen); /* Padding */
+	blake2s_compress(state, state->buf, 1, state->buflen);
+	cpu_to_le32_array(state->h, ARRAY_SIZE(state->h));
+	memcpy(out, state->h, state->outlen);
 	memzero_explicit(state, sizeof(*state));
 }
 EXPORT_SYMBOL(blake2s_final);
@@ -38,12 +66,7 @@ static int __init blake2s_mod_init(void)
 	return 0;
 }
 
-static void __exit blake2s_mod_exit(void)
-{
-}
-
 module_init(blake2s_mod_init);
-module_exit(blake2s_mod_exit);
 MODULE_LICENSE("GPL v2");
 MODULE_DESCRIPTION("BLAKE2s hash function");
 MODULE_AUTHOR("Jason A. Donenfeld <Jason@zx2c4.com>");
diff --git a/lib/sha1.c b/lib/crypto/sha1.c
index 0494766fc574..1aebe7be9401 100644
--- a/lib/sha1.c
+++ b/lib/crypto/sha1.c
@@ -8,6 +8,7 @@
 
 #include <linux/kernel.h>
 #include <linux/export.h>
+#include <linux/module.h>
 #include <linux/bitops.h>
 #include <linux/string.h>
 #include <crypto/sha1.h>
@@ -135,3 +136,5 @@ void sha1_init(__u32 *buf)
 	buf[4] = 0xc3d2e1f0;
 }
 EXPORT_SYMBOL(sha1_init);
+
+MODULE_LICENSE("GPL");
diff --git a/lib/idr.c b/lib/idr.c
index f4ab4f4aa3c7..7ecdfdb5309e 100644
--- a/lib/idr.c
+++ b/lib/idr.c
@@ -491,7 +491,8 @@ void ida_free(struct ida *ida, unsigned int id)
 	struct ida_bitmap *bitmap;
 	unsigned long flags;
 
-	BUG_ON((int)id < 0);
+	if ((int)id < 0)
+		return;
 
 	xas_lock_irqsave(&xas, flags);
 	bitmap = xas_load(&xas);
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 0b64695ab632..0e0be334dbee 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -168,174 +168,6 @@ static int copyin(void *to, const void __user *from, size_t n)
 	return n;
 }
 
-static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t bytes,
-			 struct iov_iter *i)
-{
-	size_t skip, copy, left, wanted;
-	const struct iovec *iov;
-	char __user *buf;
-	void *kaddr, *from;
-
-	if (unlikely(bytes > i->count))
-		bytes = i->count;
-
-	if (unlikely(!bytes))
-		return 0;
-
-	might_fault();
-	wanted = bytes;
-	iov = i->iov;
-	skip = i->iov_offset;
-	buf = iov->iov_base + skip;
-	copy = min(bytes, iov->iov_len - skip);
-
-	if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_writeable(buf, copy)) {
-		kaddr = kmap_atomic(page);
-		from = kaddr + offset;
-
-		/* first chunk, usually the only one */
-		left = copyout(buf, from, copy);
-		copy -= left;
-		skip += copy;
-		from += copy;
-		bytes -= copy;
-
-		while (unlikely(!left && bytes)) {
-			iov++;
-			buf = iov->iov_base;
-			copy = min(bytes, iov->iov_len);
-			left = copyout(buf, from, copy);
-			copy -= left;
-			skip = copy;
-			from += copy;
-			bytes -= copy;
-		}
-		if (likely(!bytes)) {
-			kunmap_atomic(kaddr);
-			goto done;
-		}
-		offset = from - kaddr;
-		buf += copy;
-		kunmap_atomic(kaddr);
-		copy = min(bytes, iov->iov_len - skip);
-	}
-	/* Too bad - revert to non-atomic kmap */
-
-	kaddr = kmap(page);
-	from = kaddr + offset;
-	left = copyout(buf, from, copy);
-	copy -= left;
-	skip += copy;
-	from += copy;
-	bytes -= copy;
-	while (unlikely(!left && bytes)) {
-		iov++;
-		buf = iov->iov_base;
-		copy = min(bytes, iov->iov_len);
-		left = copyout(buf, from, copy);
-		copy -= left;
-		skip = copy;
-		from += copy;
-		bytes -= copy;
-	}
-	kunmap(page);
-
-done:
-	if (skip == iov->iov_len) {
-		iov++;
-		skip = 0;
-	}
-	i->count -= wanted - bytes;
-	i->nr_segs -= iov - i->iov;
-	i->iov = iov;
-	i->iov_offset = skip;
-	return wanted - bytes;
-}
-
-static size_t copy_page_from_iter_iovec(struct page *page, size_t offset, size_t bytes,
-			 struct iov_iter *i)
-{
-	size_t skip, copy, left, wanted;
-	const struct iovec *iov;
-	char __user *buf;
-	void *kaddr, *to;
-
-	if (unlikely(bytes > i->count))
-		bytes = i->count;
-
-	if (unlikely(!bytes))
-		return 0;
-
-	might_fault();
-	wanted = bytes;
-	iov = i->iov;
-	skip = i->iov_offset;
-	buf = iov->iov_base + skip;
-	copy = min(bytes, iov->iov_len - skip);
-
-	if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_readable(buf, copy)) {
-		kaddr = kmap_atomic(page);
-		to = kaddr + offset;
-
-		/* first chunk, usually the only one */
-		left = copyin(to, buf, copy);
-		copy -= left;
-		skip += copy;
-		to += copy;
-		bytes -= copy;
-
-		while (unlikely(!left && bytes)) {
-			iov++;
-			buf = iov->iov_base;
-			copy = min(bytes, iov->iov_len);
-			left = copyin(to, buf, copy);
-			copy -= left;
-			skip = copy;
-			to += copy;
-			bytes -= copy;
-		}
-		if (likely(!bytes)) {
-			kunmap_atomic(kaddr);
-			goto done;
-		}
-		offset = to - kaddr;
-		buf += copy;
-		kunmap_atomic(kaddr);
-		copy = min(bytes, iov->iov_len - skip);
-	}
-	/* Too bad - revert to non-atomic kmap */
-
-	kaddr = kmap(page);
-	to = kaddr + offset;
-	left = copyin(to, buf, copy);
-	copy -= left;
-	skip += copy;
-	to += copy;
-	bytes -= copy;
-	while (unlikely(!left && bytes)) {
-		iov++;
-		buf = iov->iov_base;
-		copy = min(bytes, iov->iov_len);
-		left = copyin(to, buf, copy);
-		copy -= left;
-		skip = copy;
-		to += copy;
-		bytes -= copy;
-	}
-	kunmap(page);
-
-done:
-	if (skip == iov->iov_len) {
-		iov++;
-		skip = 0;
-	}
-	i->count -= wanted - bytes;
-	i->nr_segs -= iov - i->iov;
-	i->iov = iov;
-	i->iov_offset = skip;
-	return wanted - bytes;
-}
-
 #ifdef PIPE_PARANOIA
 static bool sanity(const struct iov_iter *i)
 {
@@ -689,6 +521,7 @@ static size_t copy_mc_pipe_to_iter(const void *addr, size_t bytes,
 	struct pipe_inode_info *pipe = i->pipe;
 	unsigned int p_mask = pipe->ring_size - 1;
 	unsigned int i_head;
+	unsigned int valid = pipe->head;
 	size_t n, off, xfer = 0;
 
 	if (!sanity(i))
@@ -702,11 +535,17 @@ static size_t copy_mc_pipe_to_iter(const void *addr, size_t bytes,
 		rem = copy_mc_to_kernel(p + off, addr + xfer, chunk);
 		chunk -= rem;
 		kunmap_local(p);
-		i->head = i_head;
-		i->iov_offset = off + chunk;
-		xfer += chunk;
-		if (rem)
+		if (chunk) {
+			i->head = i_head;
+			i->iov_offset = off + chunk;
+			xfer += chunk;
+			valid = i_head + 1;
+		}
+		if (rem) {
+			pipe->bufs[i_head & p_mask].len -= rem;
+			pipe_discard_from(pipe, valid);
 			break;
+		}
 		n -= chunk;
 		off = 0;
 		i_head++;
@@ -848,24 +687,14 @@ static inline bool page_copy_sane(struct page *page, size_t offset, size_t n)
 static size_t __copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
 			 struct iov_iter *i)
 {
-	if (likely(iter_is_iovec(i)))
-		return copy_page_to_iter_iovec(page, offset, bytes, i);
-	if (iov_iter_is_bvec(i) || iov_iter_is_kvec(i) || iov_iter_is_xarray(i)) {
+	if (unlikely(iov_iter_is_pipe(i))) {
+		return copy_page_to_iter_pipe(page, offset, bytes, i);
+	} else {
 		void *kaddr = kmap_local_page(page);
 		size_t wanted = _copy_to_iter(kaddr + offset, bytes, i);
 		kunmap_local(kaddr);
 		return wanted;
 	}
-	if (iov_iter_is_pipe(i))
-		return copy_page_to_iter_pipe(page, offset, bytes, i);
-	if (unlikely(iov_iter_is_discard(i))) {
-		if (unlikely(i->count < bytes))
-			bytes = i->count;
-		i->count -= bytes;
-		return bytes;
-	}
-	WARN_ON(1);
-	return 0;
 }
 
 size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
@@ -896,17 +725,12 @@ EXPORT_SYMBOL(copy_page_to_iter);
 size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
 			 struct iov_iter *i)
 {
-	if (unlikely(!page_copy_sane(page, offset, bytes)))
-		return 0;
-	if (likely(iter_is_iovec(i)))
-		return copy_page_from_iter_iovec(page, offset, bytes, i);
-	if (iov_iter_is_bvec(i) || iov_iter_is_kvec(i) || iov_iter_is_xarray(i)) {
+	if (page_copy_sane(page, offset, bytes)) {
 		void *kaddr = kmap_local_page(page);
 		size_t wanted = _copy_from_iter(kaddr + offset, bytes, i);
 		kunmap_local(kaddr);
 		return wanted;
 	}
-	WARN_ON(1);
 	return 0;
 }
 EXPORT_SYMBOL(copy_page_from_iter);
@@ -1029,17 +853,22 @@ static void pipe_advance(struct iov_iter *i, size_t size)
 
 static void iov_iter_bvec_advance(struct iov_iter *i, size_t size)
 {
-	struct bvec_iter bi;
+	const struct bio_vec *bvec, *end;
 
-	bi.bi_size = i->count;
-	bi.bi_bvec_done = i->iov_offset;
-	bi.bi_idx = 0;
-	bvec_iter_advance(i->bvec, &bi, size);
+	if (!i->count)
+		return;
+	i->count -= size;
+
+	size += i->iov_offset;
 
-	i->bvec += bi.bi_idx;
-	i->nr_segs -= bi.bi_idx;
-	i->count = bi.bi_size;
-	i->iov_offset = bi.bi_bvec_done;
+	for (bvec = i->bvec, end = bvec + i->nr_segs; bvec < end; bvec++) {
+		if (likely(size < bvec->bv_len))
+			break;
+		size -= bvec->bv_len;
+	}
+	i->iov_offset = size;
+	i->nr_segs -= bvec - i->bvec;
+	i->bvec = bvec;
 }
 
 static void iov_iter_iovec_advance(struct iov_iter *i, size_t size)
@@ -1268,6 +1097,98 @@ void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count)
 }
 EXPORT_SYMBOL(iov_iter_discard);
 
+static bool iov_iter_aligned_iovec(const struct iov_iter *i, unsigned addr_mask,
+				   unsigned len_mask)
+{
+	size_t size = i->count;
+	size_t skip = i->iov_offset;
+	unsigned k;
+
+	for (k = 0; k < i->nr_segs; k++, skip = 0) {
+		size_t len = i->iov[k].iov_len - skip;
+
+		if (len > size)
+			len = size;
+		if (len & len_mask)
+			return false;
+		if ((unsigned long)(i->iov[k].iov_base + skip) & addr_mask)
+			return false;
+
+		size -= len;
+		if (!size)
+			break;
+	}
+	return true;
+}
+
+static bool iov_iter_aligned_bvec(const struct iov_iter *i, unsigned addr_mask,
+				  unsigned len_mask)
+{
+	size_t size = i->count;
+	unsigned skip = i->iov_offset;
+	unsigned k;
+
+	for (k = 0; k < i->nr_segs; k++, skip = 0) {
+		size_t len = i->bvec[k].bv_len - skip;
+
+		if (len > size)
+			len = size;
+		if (len & len_mask)
+			return false;
+		if ((unsigned long)(i->bvec[k].bv_offset + skip) & addr_mask)
+			return false;
+
+		size -= len;
+		if (!size)
+			break;
+	}
+	return true;
+}
+
+/**
+ * iov_iter_is_aligned() - Check if the addresses and lengths of each segments
+ * 	are aligned to the parameters.
+ *
+ * @i: &struct iov_iter to restore
+ * @addr_mask: bit mask to check against the iov element's addresses
+ * @len_mask: bit mask to check against the iov element's lengths
+ *
+ * Return: false if any addresses or lengths intersect with the provided masks
+ */
+bool iov_iter_is_aligned(const struct iov_iter *i, unsigned addr_mask,
+			 unsigned len_mask)
+{
+	if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i)))
+		return iov_iter_aligned_iovec(i, addr_mask, len_mask);
+
+	if (iov_iter_is_bvec(i))
+		return iov_iter_aligned_bvec(i, addr_mask, len_mask);
+
+	if (iov_iter_is_pipe(i)) {
+		unsigned int p_mask = i->pipe->ring_size - 1;
+		size_t size = i->count;
+
+		if (size & len_mask)
+			return false;
+		if (size && allocated(&i->pipe->bufs[i->head & p_mask])) {
+			if (i->iov_offset & addr_mask)
+				return false;
+		}
+
+		return true;
+	}
+
+	if (iov_iter_is_xarray(i)) {
+		if (i->count & len_mask)
+			return false;
+		if ((i->xarray_start + i->iov_offset) & addr_mask)
+			return false;
+	}
+
+	return true;
+}
+EXPORT_SYMBOL_GPL(iov_iter_is_aligned);
+
 static unsigned long iov_iter_alignment_iovec(const struct iov_iter *i)
 {
 	unsigned long res = 0;
@@ -1465,47 +1386,36 @@ static ssize_t iter_xarray_get_pages(struct iov_iter *i,
 }
 
 /* must be done on non-empty ITER_IOVEC one */
-static unsigned long first_iovec_segment(const struct iov_iter *i,
-					 size_t *size, size_t *start,
-					 size_t maxsize, unsigned maxpages)
+static unsigned long first_iovec_segment(const struct iov_iter *i, size_t *size)
 {
 	size_t skip;
 	long k;
 
 	for (k = 0, skip = i->iov_offset; k < i->nr_segs; k++, skip = 0) {
-		unsigned long addr = (unsigned long)i->iov[k].iov_base + skip;
 		size_t len = i->iov[k].iov_len - skip;
 
 		if (unlikely(!len))
 			continue;
-		if (len > maxsize)
-			len = maxsize;
-		len += (*start = addr % PAGE_SIZE);
-		if (len > maxpages * PAGE_SIZE)
-			len = maxpages * PAGE_SIZE;
-		*size = len;
-		return addr & PAGE_MASK;
+		if (*size > len)
+			*size = len;
+		return (unsigned long)i->iov[k].iov_base + skip;
 	}
 	BUG(); // if it had been empty, we wouldn't get called
 }
 
 /* must be done on non-empty ITER_BVEC one */
 static struct page *first_bvec_segment(const struct iov_iter *i,
-				       size_t *size, size_t *start,
-				       size_t maxsize, unsigned maxpages)
+				       size_t *size, size_t *start)
 {
 	struct page *page;
 	size_t skip = i->iov_offset, len;
 
 	len = i->bvec->bv_len - skip;
-	if (len > maxsize)
-		len = maxsize;
+	if (*size > len)
+		*size = len;
 	skip += i->bvec->bv_offset;
 	page = i->bvec->bv_page + skip / PAGE_SIZE;
-	len += (*start = skip % PAGE_SIZE);
-	if (len > maxpages * PAGE_SIZE)
-		len = maxpages * PAGE_SIZE;
-	*size = len;
+	*start = skip % PAGE_SIZE;
 	return page;
 }
 
@@ -1513,13 +1423,14 @@ ssize_t iov_iter_get_pages(struct iov_iter *i,
 		   struct page **pages, size_t maxsize, unsigned maxpages,
 		   size_t *start)
 {
-	size_t len;
 	int n, res;
 
 	if (maxsize > i->count)
 		maxsize = i->count;
 	if (!maxsize)
 		return 0;
+	if (maxsize > MAX_RW_COUNT)
+		maxsize = MAX_RW_COUNT;
 
 	if (likely(iter_is_iovec(i))) {
 		unsigned int gup_flags = 0;
@@ -1530,21 +1441,27 @@ ssize_t iov_iter_get_pages(struct iov_iter *i,
 		if (i->nofault)
 			gup_flags |= FOLL_NOFAULT;
 
-		addr = first_iovec_segment(i, &len, start, maxsize, maxpages);
-		n = DIV_ROUND_UP(len, PAGE_SIZE);
+		addr = first_iovec_segment(i, &maxsize);
+		*start = addr % PAGE_SIZE;
+		addr &= PAGE_MASK;
+		n = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE);
+		if (n > maxpages)
+			n = maxpages;
 		res = get_user_pages_fast(addr, n, gup_flags, pages);
 		if (unlikely(res <= 0))
 			return res;
-		return (res == n ? len : res * PAGE_SIZE) - *start;
+		return min_t(size_t, maxsize, res * PAGE_SIZE - *start);
 	}
 	if (iov_iter_is_bvec(i)) {
 		struct page *page;
 
-		page = first_bvec_segment(i, &len, start, maxsize, maxpages);
-		n = DIV_ROUND_UP(len, PAGE_SIZE);
-		while (n--)
+		page = first_bvec_segment(i, &maxsize, start);
+		n = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE);
+		if (n > maxpages)
+			n = maxpages;
+		for (int k = 0; k < n; k++)
 			get_page(*pages++ = page++);
-		return len - *start;
+		return min_t(size_t, maxsize, n * PAGE_SIZE - *start);
 	}
 	if (iov_iter_is_pipe(i))
 		return pipe_get_pages(i, pages, maxsize, maxpages, start);
@@ -1633,13 +1550,14 @@ ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
 		   size_t *start)
 {
 	struct page **p;
-	size_t len;
 	int n, res;
 
 	if (maxsize > i->count)
 		maxsize = i->count;
 	if (!maxsize)
 		return 0;
+	if (maxsize > MAX_RW_COUNT)
+		maxsize = MAX_RW_COUNT;
 
 	if (likely(iter_is_iovec(i))) {
 		unsigned int gup_flags = 0;
@@ -