https://github.com/torvalds/linux
Revision 9f79b78ef74436c7507bac6bfb7b8b989263bccb authored by Linus Torvalds on 22 May 2016, 04:59:07 UTC, committed by Linus Torvalds on 05 October 2019, 19:00:36 UTC
We really should avoid the "__{get,put}_user()" functions entirely, because they can easily be mis-used and the original intent of being used for simple direct user accesses no longer holds in a post-SMAP/PAN world. Manually optimizing away the user access range check makes no sense any more, when the range check is generally much cheaper than the "enable user accesses" code that the __{get,put}_user() functions still need. So instead of __put_user(), use the unsafe_put_user() interface with user_access_{begin,end}() that really does generate better code these days, and which is generally a nicer interface. Under some loads, the multiple user writes that filldir() does are actually quite noticeable. This also makes the dirent name copy use unsafe_put_user() with a couple of macros. We do not want to make function calls with SMAP/PAN disabled, and the code this generates is quite good when the architecture uses "asm goto" for unsafe_put_user() like x86 does. Note that this doesn't bother with the legacy cases. Nobody should use them anyway, so performance doesn't really matter there. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Tip revision: 9f79b78ef74436c7507bac6bfb7b8b989263bccb authored by Linus Torvalds on 22 May 2016, 04:59:07 UTC
Convert filldir[64]() from __put_user() to unsafe_put_user()
Convert filldir[64]() from __put_user() to unsafe_put_user()
Tip revision: 9f79b78
File | Mode | Size |
---|---|---|
Documentation | ||
LICENSES | ||
arch | ||
block | ||
certs | ||
crypto | ||
drivers | ||
fs | ||
include | ||
init | ||
ipc | ||
kernel | ||
lib | ||
mm | ||
net | ||
samples | ||
scripts | ||
security | ||
sound | ||
tools | ||
usr | ||
virt | ||
.clang-format | -rw-r--r-- | 15.0 KB |
.cocciconfig | -rw-r--r-- | 59 bytes |
.get_maintainer.ignore | -rw-r--r-- | 71 bytes |
.gitattributes | -rw-r--r-- | 30 bytes |
.gitignore | -rw-r--r-- | 1.7 KB |
.mailmap | -rw-r--r-- | 12.5 KB |
COPYING | -rw-r--r-- | 423 bytes |
CREDITS | -rw-r--r-- | 97.1 KB |
Kbuild | -rw-r--r-- | 1.5 KB |
Kconfig | -rw-r--r-- | 595 bytes |
MAINTAINERS | -rw-r--r-- | 510.9 KB |
Makefile | -rw-r--r-- | 59.7 KB |
README | -rw-r--r-- | 727 bytes |
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