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

[linux.git] / fs / select.c

diff --git a/fs/select.c b/fs/select.c
index a8109baa5e46429a894664eba4bfe1ce25f4b89b..f163db20eb5a3b911afe5cf677f40d56a7caaed5 100644 (file)
--- a/fs/select.c
+++ b/fs/select.c
@@ -17,7 +17,6 @@
 #include <linux/syscalls.h>
 #include <linux/module.h>
 #include <linux/slab.h>
-#include <linux/smp_lock.h>
 #include <linux/poll.h>
 #include <linux/personality.h> /* for STICKY_TIMEOUTS */
 #include <linux/file.h>
@@ -311,7 +310,7 @@ static int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp,
 {
        fd_set_bits fds;
        void *bits;
-       int ret, max_fdset;
+       int ret, max_fds;
        unsigned int size;
        struct fdtable *fdt;
        /* Allocate small arguments on the stack to save memory and be faster */
@@ -321,13 +320,13 @@ static int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp,
        if (n < 0)
                goto out_nofds;
 
-       /* max_fdset can increase, so grab it once to avoid race */
+       /* max_fds can increase, so grab it once to avoid race */
        rcu_read_lock();
        fdt = files_fdtable(current->files);
-       max_fdset = fdt->max_fdset;
+       max_fds = fdt->max_fds;
        rcu_read_unlock();
-       if (n > max_fdset)
-               n = max_fdset;
+       if (n > max_fds)
+               n = max_fds;
 
        /*
         * We need 6 bitmaps (in/out/ex for both incoming and outgoing),
@@ -546,37 +545,38 @@ struct poll_list {
 
 #define POLLFD_PER_PAGE  ((PAGE_SIZE-sizeof(struct poll_list)) / sizeof(struct pollfd))
 
-static void do_pollfd(unsigned int num, struct pollfd * fdpage,
-       poll_table ** pwait, int *count)
+/*
+ * Fish for pollable events on the pollfd->fd file descriptor. We're only
+ * interested in events matching the pollfd->events mask, and the result
+ * matching that mask is both recorded in pollfd->revents and returned. The
+ * pwait poll_table will be used by the fd-provided poll handler for waiting,
+ * if non-NULL.
+ */
+static inline unsigned int do_pollfd(struct pollfd *pollfd, poll_table *pwait)
 {
-       int i;
-
-       for (i = 0; i < num; i++) {
-               int fd;
-               unsigned int mask;
-               struct pollfd *fdp;
-
-               mask = 0;
-               fdp = fdpage+i;
-               fd = fdp->fd;
-               if (fd >= 0) {
-                       int fput_needed;
-                       struct file * file = fget_light(fd, &fput_needed);
-                       mask = POLLNVAL;
-                       if (file != NULL) {
-                               mask = DEFAULT_POLLMASK;
-                               if (file->f_op && file->f_op->poll)
-                                       mask = file->f_op->poll(file, *pwait);
-                               mask &= fdp->events | POLLERR | POLLHUP;
-                               fput_light(file, fput_needed);
-                       }
-                       if (mask) {
-                               *pwait = NULL;
-                               (*count)++;
-                       }
+       unsigned int mask;
+       int fd;
+
+       mask = 0;
+       fd = pollfd->fd;
+       if (fd >= 0) {
+               int fput_needed;
+               struct file * file;
+
+               file = fget_light(fd, &fput_needed);
+               mask = POLLNVAL;
+               if (file != NULL) {
+                       mask = DEFAULT_POLLMASK;
+                       if (file->f_op && file->f_op->poll)
+                               mask = file->f_op->poll(file, pwait);
+                       /* Mask out unneeded events. */
+                       mask &= pollfd->events | POLLERR | POLLHUP;
+                       fput_light(file, fput_needed);
                }
-               fdp->revents = mask;
        }
+       pollfd->revents = mask;
+
+       return mask;
 }
 
 static int do_poll(unsigned int nfds,  struct poll_list *list,
@@ -594,11 +594,29 @@ static int do_poll(unsigned int nfds,  struct poll_list *list,
                long __timeout;
 
                set_current_state(TASK_INTERRUPTIBLE);
-               walk = list;
-               while(walk != NULL) {
-                       do_pollfd( walk->len, walk->entries, &pt, &count);
-                       walk = walk->next;
+               for (walk = list; walk != NULL; walk = walk->next) {
+                       struct pollfd * pfd, * pfd_end;
+
+                       pfd = walk->entries;
+                       pfd_end = pfd + walk->len;
+                       for (; pfd != pfd_end; pfd++) {
+                               /*
+                                * Fish for events. If we found one, record it
+                                * and kill the poll_table, so we don't
+                                * needlessly register any other waiters after
+                                * this. They'll get immediately deregistered
+                                * when we break out and return.
+                                */
+                               if (do_pollfd(pfd, pt)) {
+                                       count++;
+                                       pt = NULL;
+                               }
+                       }
                }
+               /*
+                * All waiters have already been registered, so don't provide
+                * a poll_table to them on the next loop iteration.
+                */
                pt = NULL;
                if (count || !*timeout || signal_pending(current))
                        break;
@@ -639,8 +657,6 @@ int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds, s64 *timeout)
        unsigned int i;
        struct poll_list *head;
        struct poll_list *walk;
-       struct fdtable *fdt;
-       int max_fdset;
        /* Allocate small arguments on the stack to save memory and be
           faster - use long to make sure the buffer is aligned properly
           on 64 bit archs to avoid unaligned access */
@@ -648,11 +664,7 @@ int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds, s64 *timeout)
        struct poll_list *stack_pp = NULL;
 
        /* Do a sanity check on nfds ... */
-       rcu_read_lock();
-       fdt = files_fdtable(current->files);
-       max_fdset = fdt->max_fdset;
-       rcu_read_unlock();
-       if (nfds > max_fdset && nfds > OPEN_MAX)
+       if (nfds > current->signal->rlim[RLIMIT_NOFILE].rlim_cur)
                return -EINVAL;
 
        poll_initwait(&table);
@@ -727,9 +739,9 @@ out_fds:
 asmlinkage long sys_poll(struct pollfd __user *ufds, unsigned int nfds,
                        long timeout_msecs)
 {
-       s64 timeout_jiffies = 0;
+       s64 timeout_jiffies;
 
-       if (timeout_msecs) {
+       if (timeout_msecs > 0) {
 #if HZ > 1000
                /* We can only overflow if HZ > 1000 */
                if (timeout_msecs / 1000 > (s64)0x7fffffffffffffffULL / (s64)HZ)
@@ -737,6 +749,9 @@ asmlinkage long sys_poll(struct pollfd __user *ufds, unsigned int nfds,
                else
 #endif
                        timeout_jiffies = msecs_to_jiffies(timeout_msecs);
+       } else {
+               /* Infinite (< 0) or no (0) timeout */
+               timeout_jiffies = timeout_msecs;
        }
 
        return do_sys_poll(ufds, nfds, &timeout_jiffies);