From 279b2b827810d149b5b8453900cdea57874ae234 Mon Sep 17 00:00:00 2001 From: jhb Date: Wed, 4 Feb 2004 21:52:57 +0000 Subject: Locking for the per-process resource limits structure. - struct plimit includes a mutex to protect a reference count. The plimit structure is treated similarly to struct ucred in that is is always copy on write, so having a reference to a structure is sufficient to read from it without needing a further lock. - The proc lock protects the p_limit pointer and must be held while reading limits from a process to keep the limit structure from changing out from under you while reading from it. - Various global limits that are ints are not protected by a lock since int writes are atomic on all the archs we support and thus a lock wouldn't buy us anything. - All accesses to individual resource limits from a process are abstracted behind a simple lim_rlimit(), lim_max(), and lim_cur() API that return either an rlimit, or the current or max individual limit of the specified resource from a process. - dosetrlimit() was renamed to kern_setrlimit() to match existing style of other similar syscall helper functions. - The alpha OSF/1 compat layer no longer calls getrlimit() and setrlimit() (it didn't used the stackgap when it should have) but uses lim_rlimit() and kern_setrlimit() instead. - The svr4 compat no longer uses the stackgap for resource limits calls, but uses lim_rlimit() and kern_setrlimit() instead. - The ibcs2 compat no longer uses the stackgap for resource limits. It also no longer uses the stackgap for accessing sysctl's for the ibcs2_sysconf() syscall but uses kernel_sysctl() instead. As a result, ibcs2_sysconf() no longer needs Giant. - The p_rlimit macro no longer exists. Submitted by: mtm (mostly, I only did a few cleanups and catchups) Tested on: i386 Compiled on: alpha, amd64 --- sys/fs/fdescfs/fdesc_vfsops.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'sys/fs/fdescfs') diff --git a/sys/fs/fdescfs/fdesc_vfsops.c b/sys/fs/fdescfs/fdesc_vfsops.c index a958308..c80e8eb 100644 --- a/sys/fs/fdescfs/fdesc_vfsops.c +++ b/sys/fs/fdescfs/fdesc_vfsops.c @@ -169,7 +169,9 @@ fdesc_statfs(mp, sbp, td) * limit is ever reduced below the current number * of open files... ] */ - lim = td->td_proc->p_rlimit[RLIMIT_NOFILE].rlim_cur; + PROC_LOCK(td->td_proc); + lim = lim_cur(td->td_proc, RLIMIT_NOFILE); + PROC_UNLOCK(td->td_proc); fdp = td->td_proc->p_fd; FILEDESC_LOCK(fdp); last = min(fdp->fd_nfiles, lim); -- cgit v1.1