kernel/linux.git/lib/iov_iter.c, branch v5.1.10

iov_iter: Fix build error without CONFIG_CRYPTO

2019-04-04T02:37:41+00:00

If CONFIG_CRYPTO is not set or set to m, gcc building warn this: lib/iov_iter.o: In function `hash_and_copy_to_iter': iov_iter.c:(.text+0x9129): undefined reference to `crypto_stats_get' iov_iter.c:(.text+0x9152): undefined reference to `crypto_stats_ahash_update' Reported-by: Hulk Robot Fixes: d05f443554b3 ("iov_iter: introduce hash_and_copy_to_iter helper") Suggested-by: Al Viro Signed-off-by: YueHaibing Signed-off-by: Al Viro

iov_iter: optimize page_copy_sane()

2019-02-26T19:05:20+00:00

Avoid cache line miss dereferencing struct page if we can. page_copy_sane() mostly deals with order-0 pages. Extra cache line miss is visible on TCP recvmsg() calls dealing with GRO packets (typically 45 page frags are attached to one skb). Bringing the 45 struct pages into cpu cache while copying the data is not free, since the freeing of the skb (and associated page frags put_page()) can happen after cache lines have been evicted. Signed-off-by: Eric Dumazet Cc: Al Viro Signed-off-by: Al Viro

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2019-01-05T21:18:59+00:00

Pull trivial vfs updates from Al Viro: "A few cleanups + Neil's namespace_unlock() optimization" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: exec: make prepare_bprm_creds static genheaders: %-s had been there since v6; %-*s - since v7 VFS: use synchronize_rcu_expedited() in namespace_unlock() iov_iter: reduce code duplication

Remove 'type' argument from access_ok() function

2019-01-04T02:57:57+00:00

Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument of the user address range verification function since we got rid of the old racy i386-only code to walk page tables by hand. It existed because the original 80386 would not honor the write protect bit when in kernel mode, so you had to do COW by hand before doing any user access. But we haven't supported that in a long time, and these days the 'type' argument is a purely historical artifact. A discussion about extending 'user_access_begin()' to do the range checking resulted this patch, because there is no way we're going to move the old VERIFY_xyz interface to that model. And it's best done at the end of the merge window when I've done most of my merges, so let's just get this done once and for all. This patch was mostly done with a sed-script, with manual fix-ups for the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form. There were a couple of notable cases: - csky still had the old "verify_area()" name as an alias. - the iter_iov code had magical hardcoded knowledge of the actual values of VERIFY_{READ,WRITE} (not that they mattered, since nothing really used it) - microblaze used the type argument for a debug printout but other than those oddities this should be a total no-op patch. I tried to fix up all architectures, did fairly extensive grepping for access_ok() uses, and the changes are trivial, but I may have missed something. Any missed conversion should be trivially fixable, though. Signed-off-by: Linus Torvalds

iov_iter: introduce hash_and_copy_to_iter helper

2018-12-13T08:58:54+00:00

Allow consumers that want to use iov iterator helpers and also update a predefined hash calculation online when copying data. This is useful when copying incoming network buffers to a local iterator and calculate a digest on the incoming stream. nvme-tcp host driver that will be introduced in following patches is the first consumer via skb_copy_and_hash_datagram_iter. Acked-by: David S. Miller Signed-off-by: Sagi Grimberg Signed-off-by: Christoph Hellwig

iov_iter: pass void csum pointer to csum_and_copy_to_iter

2018-12-13T08:58:53+00:00

The single caller to csum_and_copy_to_iter is skb_copy_and_csum_datagram and we are trying to unite its logic with skb_copy_datagram_iter by passing a callback to the copy function that we want to apply. Thus, we need to make the checksum pointer private to the function. Acked-by: David S. Miller Signed-off-by: Sagi Grimberg Signed-off-by: Christoph Hellwig

iov_iter: reduce code duplication

2018-11-28T03:35:08+00:00

The same combination of csum_partial_copy_nocheck() with csum_add_block() is used in a bunch of places. Add a helper doing just that and use it. Signed-off-by: Al Viro

iov_iter: teach csum_and_copy_to_iter() to handle pipe-backed ones

2018-11-25T21:24:49+00:00

Signed-off-by: Al Viro

iov_iter: Add I/O discard iterator

2018-10-23T23:41:07+00:00

Add a new iterator, ITER_DISCARD, that can only be used in READ mode and just discards any data copied to it. This is useful in a network filesystem for discarding any unwanted data sent by a server. Signed-off-by: David Howells

iov_iter: Separate type from direction and use accessor functions

2018-10-23T23:41:07+00:00

In the iov_iter struct, separate the iterator type from the iterator direction and use accessor functions to access them in most places. Convert a bunch of places to use switch-statements to access them rather then chains of bitwise-AND statements. This makes it easier to add further iterator types. Also, this can be more efficient as to implement a switch of small contiguous integers, the compiler can use ~50% fewer compare instructions than it has to use bitwise-and instructions. Further, cease passing the iterator type into the iterator setup function. The iterator function can set that itself. Only the direction is required. Signed-off-by: David Howells