linux-toradex.git/fs/select.c, branch v2.6.22.13

Style fix in fs/select.c

2007-05-09T05:10:02+00:00

Signed-off-by: WANG Cong  
Signed-off-by: Adrian Bunk

ROUND_UP macro cleanup in fs/(select|compat|readdir).c

2007-05-08T18:15:09+00:00

ROUND_UP macro cleanup use,ALIGN or DIV_ROUND_UP where ever appropriate.

Signed-off-by: Milind Arun Choudhary 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

header cleaning: don't include smp_lock.h when not used

2007-05-08T18:15:07+00:00

Remove includes of  where it is not used/needed.
Suggested by Al Viro.

Builds cleanly on x86_64, i386, alpha, ia64, powerpc, sparc,
sparc64, and arm (all 59 defconfigs).

Signed-off-by: Randy Dunlap 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] fdtable: Make fdarray and fdsets equal in size

2006-12-10T17:57:22+00:00

Currently, each fdtable supports three dynamically-sized arrays of data: the
fdarray and two fdsets.  The code allows the number of fds supported by the
fdarray (fdtable->max_fds) to differ from the number of fds supported by each
of the fdsets (fdtable->max_fdset).

In practice, it is wasteful for these two sizes to differ: whenever we hit a
limit on the smaller-capacity structure, we will reallocate the entire fdtable
and all the dynamic arrays within it, so any delta in the memory used by the
larger-capacity structure will never be touched at all.

Rather than hogging this excess, we shouldn't even allocate it in the first
place, and keep the capacities of the fdarray and the fdsets equal.  This
patch removes fdtable->max_fdset.  As an added bonus, most of the supporting
code becomes simpler.

Signed-off-by: Vadim Lobanov 
Cc: Christoph Hellwig 
Cc: Al Viro 
Cc: Dipankar Sarma 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] enforce RLIMIT_NOFILE in poll()

2006-09-29T16:18:23+00:00

POSIX states that poll() shall fail with EINVAL if nfds > OPEN_MAX.  In
this context, POSIX is referring to sysconf(OPEN_MAX), which is the value
of current->signal->rlim[RLIMIT_NOFILE].rlim_cur in the linux kernel, not
the compile-time constant which happens to also be named OPEN_MAX.  In the
current code, an application may poll up to max_fdset file descriptors,
even if this exceeds RLIMIT_NOFILE.  The current code also breaks
applications which poll more than max_fdset descriptors, which worked circa
2.4.18 when the check was against NR_OPEN, which is 1024*1024.  This patch
enforces the limit precisely as POSIX defines, even if RLIMIT_NOFILE has
been changed at run time with ulimit -n.

To elaborate on the rationale for this, there are three cases:

1) RLIMIT_NOFILE is at the default value of 1024

In this (default) case, the patch changes nothing.  Calls with nfds > 1024
fail with EINVAL both before and after the patch, and calls with nfds <=
1024 pass the check both before and after the patch, since 1024 is the
initial value of max_fdset.

2) RLIMIT_NOFILE has been raised above the default

In this case, poll() becomes more permissive, allowing polling up to
RLIMIT_NOFILE file descriptors even if less than 1024 have been opened.
The patch won't introduce new errors here.  If an application somehow
depends on poll() failing when it polls with duplicate or invalid file
descriptors, it's already broken, since this is already allowed below 1024,
and will also work above 1024 if enough file descriptors have been open at
some point to cause max_fdset to have been increased above nfds.

3) RLIMIT_NOFILE has been lowered below the default

In this case, the system administrator or the user has gone out of their
way to protect the system from inefficient (or malicious) applications
wasting kernel memory.  The current code allows polling up to 1024 file
descriptors even if RLIMIT_NOFILE is much lower, which is not what the user
or administrator intended.  Well-written applications which only poll
valid, unique file descriptors will never notice the difference, because
they'll hit the limit on open() first.  If an application gets broken
because of the patch in this case, then it was already poorly/maliciously
designed, and allowing it to work in the past was a violation of POSIX and
a DoS risk on low-resource systems.

With this patch, poll() will permit exactly what POSIX suggests, no more,
no less, and for any run-time value set with ulimit -n, not just 256 or
1024.  There are existing apps which which poll a large number of file
descriptors, some of which may be invalid, and if those numbers stradle
1024, they currently fail with or without the patch in -mm, though they
worked fine under 2.4.18.

Signed-off-by: Chris Snook 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] fs: sys_poll with timeout -1 bug fix

2006-06-25T17:01:22+00:00

If you do a poll() call with timeout -1, the wait will be a big number
(depending on HZ) instead of infinite wait, since -1 is passed to the
msecs_to_jiffies function.

Signed-off-by: Frode Isaksen 
Acked-by: Nishanth Aravamudan 
Cc: David Woodhouse 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] Poll cleanups/microoptimizations

2006-06-23T14:43:03+00:00

The "count" and "pt" variables are declared and modified by do_poll(), as
well as accessed and written indirectly in the do_pollfd() subroutine.

This patch pulls all handling of these variables into the do_poll()
function, thereby eliminating the odd use of indirection in do_pollfd().
This is done by pulling the "struct pollfd" traversal loop from do_pollfd()
into its only caller do_poll().  As an added bonus, the patch saves a few
clock cycles, and also adds comments to make the code easier to follow.

Signed-off-by: Vadim Lobanov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] select: don't overflow if (SELECT_STACK_ALLOC % sizeof(long) != 0)

2006-04-11T13:18:41+00:00

If SELECT_STACK_ALLOC is not a multiple of sizeof(long) then stack_fds[]
would be shorter than SELECT_STACK_ALLOC bytes and could overflow later in
the function.  Fixed by simply rearranging the test later to work on
sizeof(stack_fds) Currently SELECT_STACK_ALLOC is 256 so this doesn't
happen, but it's nasty to have things like this hidden in the code.  What
if later someone decides to change SELECT_STACK_ALLOC to 300?

Signed-off-by: Mitchell Blank Jr 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] select() warning fixes

2006-04-11T13:18:30+00:00

fs/select.c: In function `core_sys_select':
fs/select.c:339: warning: assignment from incompatible pointer type
fs/select.c:376: warning: comparison of distinct pointer types lacks a cast

By using a void* we can remove lots of casts rather than adding more.

Cc: Jes Sorensen 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] avoid unaligned access when accessing poll stack

2006-03-31T20:30:48+00:00

Commit 70674f95c0a2ea694d5c39f4e514f538a09be36f:

  [PATCH] Optimize select/poll by putting small data sets on the stack

resulted in the poll stack being 4-byte aligned on 64-bit architectures,
causing misaligned accesses to elements in the array.

This patch fixes it by declaring the stack in terms of 'long' instead
of 'char'.

Force alignment of poll and select stacks to long to avoid unaligned
access on 64 bit architectures.

Signed-off-by: Jes Sorensen 
Signed-off-by: Linus Torvalds