X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=fs%2Fselect.c;h=fe0893afd931e02081eca0b968e30a19e7ce2a73;hb=97bf2856c6014879bd04983a3e9dfcdac1e7fe85;hp=8cd6dc31fbb657d34fcf40ad4e6376ec90028947;hpb=43bc926fffd92024b46cafaf7350d669ba9ca884;p=linux-2.6.git diff --git a/fs/select.c b/fs/select.c index 8cd6dc31f..fe0893afd 100644 --- a/fs/select.c +++ b/fs/select.c @@ -23,7 +23,6 @@ #include #include #include -#include #include @@ -66,8 +65,7 @@ EXPORT_SYMBOL(poll_initwait); static void free_poll_entry(struct poll_table_entry *entry) { - if (remove_wait_queue(entry->wait_address,&entry->wait) < 0) - print_symbol("bad poll-entry for %s", (unsigned long) entry->filp->f_op->poll); + remove_wait_queue(entry->wait_address,&entry->wait); fput(entry->filp); } @@ -313,7 +311,7 @@ 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 */ @@ -323,13 +321,13 @@ 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), @@ -548,37 +546,38 @@ 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, @@ -596,11 +595,29 @@ 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; @@ -641,8 +658,6 @@ 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 */ @@ -650,11 +665,7 @@ 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); @@ -729,9 +740,9 @@ 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) @@ -739,6 +750,9 @@ 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);