Revision 17d51b10d7773e4618bcac64648f30f12d4078fb authored by Martin Wilck on 25 July 2018, 21:15:09 UTC, committed by Jens Axboe on 26 July 2018, 17:52:36 UTC
bio_iov_iter_get_pages() currently only adds pages for the next non-zero segment from the iov_iter to the bio. That's suboptimal for callers, which typically try to pin as many pages as fit into the bio. This patch converts the current bio_iov_iter_get_pages() into a static helper, and introduces a new helper that allocates as many pages as 1) fit into the bio, 2) are present in the iov_iter, 3) and can be pinned by MM. Error is returned only if zero pages could be pinned. Because of 3), a zero return value doesn't necessarily mean all pages have been pinned. Callers that have to pin every page in the iov_iter must still call this function in a loop (this is currently the case). This change matters most for __blkdev_direct_IO_simple(), which calls bio_iov_iter_get_pages() only once. If it obtains less pages than requested, it returns a "short write" or "short read", and __generic_file_write_iter() falls back to buffered writes, which may lead to data corruption. Fixes: 72ecad22d9f1 ("block: support a full bio worth of IO for simplified bdev direct-io") Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Martin Wilck <mwilck@suse.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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File | Mode | Size |
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Documentation | ||
LICENSES | ||
arch | ||
block | ||
certs | ||
crypto | ||
drivers | ||
firmware | ||
fs | ||
include | ||
init | ||
ipc | ||
kernel | ||
lib | ||
mm | ||
net | ||
samples | ||
scripts | ||
security | ||
sound | ||
tools | ||
usr | ||
virt | ||
.clang-format | -rw-r--r-- | 12.8 KB |
.cocciconfig | -rw-r--r-- | 59 bytes |
.get_maintainer.ignore | -rw-r--r-- | 31 bytes |
.gitattributes | -rw-r--r-- | 30 bytes |
.gitignore | -rw-r--r-- | 1.5 KB |
.mailmap | -rw-r--r-- | 9.3 KB |
COPYING | -rw-r--r-- | 423 bytes |
CREDITS | -rw-r--r-- | 96.3 KB |
Kbuild | -rw-r--r-- | 2.2 KB |
Kconfig | -rw-r--r-- | 321 bytes |
MAINTAINERS | -rw-r--r-- | 447.9 KB |
Makefile | -rw-r--r-- | 61.1 KB |
README | -rw-r--r-- | 800 bytes |
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