#define ROUND_UP(x,y) (((x)+(y)-1)/(y))
#define DEFAULT_POLLMASK (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM)
-struct poll_table_entry {
- struct file * filp;
- wait_queue_t wait;
- wait_queue_head_t * wait_address;
-};
-
struct poll_table_page {
struct poll_table_page * next;
struct poll_table_entry * entry;
init_poll_funcptr(&pwq->pt, __pollwait);
pwq->error = 0;
pwq->table = NULL;
+ pwq->inline_index = 0;
}
EXPORT_SYMBOL(poll_initwait);
+static void free_poll_entry(struct poll_table_entry *entry)
+{
+ remove_wait_queue(entry->wait_address,&entry->wait);
+ fput(entry->filp);
+}
+
void poll_freewait(struct poll_wqueues *pwq)
{
struct poll_table_page * p = pwq->table;
+ int i;
+ for (i = 0; i < pwq->inline_index; i++)
+ free_poll_entry(pwq->inline_entries + i);
while (p) {
struct poll_table_entry * entry;
struct poll_table_page *old;
entry = p->entry;
do {
entry--;
- remove_wait_queue(entry->wait_address,&entry->wait);
- fput(entry->filp);
+ free_poll_entry(entry);
} while (entry > p->entries);
old = p;
p = p->next;
EXPORT_SYMBOL(poll_freewait);
-static void __pollwait(struct file *filp, wait_queue_head_t *wait_address,
- poll_table *_p)
+static struct poll_table_entry *poll_get_entry(poll_table *_p)
{
struct poll_wqueues *p = container_of(_p, struct poll_wqueues, pt);
struct poll_table_page *table = p->table;
+ if (p->inline_index < N_INLINE_POLL_ENTRIES)
+ return p->inline_entries + p->inline_index++;
+
if (!table || POLL_TABLE_FULL(table)) {
struct poll_table_page *new_table;
if (!new_table) {
p->error = -ENOMEM;
__set_current_state(TASK_RUNNING);
- return;
+ return NULL;
}
new_table->entry = new_table->entries;
new_table->next = table;
table = new_table;
}
- /* Add a new entry */
- {
- struct poll_table_entry * entry = table->entry;
- table->entry = entry+1;
- get_file(filp);
- entry->filp = filp;
- entry->wait_address = wait_address;
- init_waitqueue_entry(&entry->wait, current);
- add_wait_queue(wait_address,&entry->wait);
- }
+ return table->entry++;
+}
+
+/* Add a new entry */
+static void __pollwait(struct file *filp, wait_queue_head_t *wait_address,
+ poll_table *p)
+{
+ struct poll_table_entry *entry = poll_get_entry(p);
+ if (!entry)
+ return;
+ get_file(filp);
+ entry->filp = filp;
+ entry->wait_address = wait_address;
+ init_waitqueue_entry(&entry->wait, current);
+ add_wait_queue(wait_address,&entry->wait);
}
#define FDS_IN(fds, n) (fds->in + n)
for (i = 0; i < n; ++rinp, ++routp, ++rexp) {
unsigned long in, out, ex, all_bits, bit = 1, mask, j;
unsigned long res_in = 0, res_out = 0, res_ex = 0;
- struct file_operations *f_op = NULL;
+ const struct file_operations *f_op = NULL;
struct file *file = NULL;
in = *inp++; out = *outp++; ex = *exp++;
}
for (j = 0; j < __NFDBITS; ++j, ++i, bit <<= 1) {
+ int fput_needed;
if (i >= n)
break;
if (!(bit & all_bits))
continue;
- file = fget(i);
+ file = fget_light(i, &fput_needed);
if (file) {
f_op = file->f_op;
mask = DEFAULT_POLLMASK;
if (f_op && f_op->poll)
mask = (*f_op->poll)(file, retval ? NULL : wait);
- fput(file);
+ fput_light(file, fput_needed);
if ((mask & POLLIN_SET) && (in & bit)) {
res_in |= bit;
retval++;
return retval;
}
-static void *select_bits_alloc(int size)
-{
- return kmalloc(6 * size, GFP_KERNEL);
-}
-
-static void select_bits_free(void *bits, int size)
-{
- kfree(bits);
-}
-
/*
* We can actually return ERESTARTSYS instead of EINTR, but I'd
* like to be certain this leads to no problems. So I return
fd_set __user *exp, s64 *timeout)
{
fd_set_bits fds;
- char *bits;
- int ret, size, max_fdset;
+ void *bits;
+ int ret, max_fdset;
+ unsigned int size;
struct fdtable *fdt;
+ /* Allocate small arguments on the stack to save memory and be faster */
+ long stack_fds[SELECT_STACK_ALLOC/sizeof(long)];
ret = -EINVAL;
if (n < 0)
* since we used fdset we need to allocate memory in units of
* long-words.
*/
- ret = -ENOMEM;
size = FDS_BYTES(n);
- bits = select_bits_alloc(size);
- if (!bits)
- goto out_nofds;
- fds.in = (unsigned long *) bits;
- fds.out = (unsigned long *) (bits + size);
- fds.ex = (unsigned long *) (bits + 2*size);
- fds.res_in = (unsigned long *) (bits + 3*size);
- fds.res_out = (unsigned long *) (bits + 4*size);
- fds.res_ex = (unsigned long *) (bits + 5*size);
+ bits = stack_fds;
+ if (size > sizeof(stack_fds) / 6) {
+ /* Not enough space in on-stack array; must use kmalloc */
+ ret = -ENOMEM;
+ bits = kmalloc(6 * size, GFP_KERNEL);
+ if (!bits)
+ goto out_nofds;
+ }
+ fds.in = bits;
+ fds.out = bits + size;
+ fds.ex = bits + 2*size;
+ fds.res_in = bits + 3*size;
+ fds.res_out = bits + 4*size;
+ fds.res_ex = bits + 5*size;
if ((ret = get_fd_set(n, inp, fds.in)) ||
(ret = get_fd_set(n, outp, fds.out)) ||
ret = -EFAULT;
out:
- select_bits_free(bits, size);
+ if (bits != stack_fds)
+ kfree(bits);
out_nofds:
return ret;
}
#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) {
- struct file * file = fget(fd);
- 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(file);
- }
- 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,
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;
return count;
}
+#define N_STACK_PPS ((sizeof(stack_pps) - sizeof(struct poll_list)) / \
+ sizeof(struct pollfd))
+
int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds, s64 *timeout)
{
struct poll_wqueues table;
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 */
+ long stack_pps[POLL_STACK_ALLOC/sizeof(long)];
+ struct poll_list *stack_pp = NULL;
/* Do a sanity check on nfds ... */
rcu_read_lock();
err = -ENOMEM;
while(i!=0) {
struct poll_list *pp;
- pp = kmalloc(sizeof(struct poll_list)+
- sizeof(struct pollfd)*
- (i>POLLFD_PER_PAGE?POLLFD_PER_PAGE:i),
- GFP_KERNEL);
- if(pp==NULL)
- goto out_fds;
+ int num, size;
+ if (stack_pp == NULL)
+ num = N_STACK_PPS;
+ else
+ num = POLLFD_PER_PAGE;
+ if (num > i)
+ num = i;
+ size = sizeof(struct poll_list) + sizeof(struct pollfd)*num;
+ if (!stack_pp)
+ stack_pp = pp = (struct poll_list *)stack_pps;
+ else {
+ pp = kmalloc(size, GFP_KERNEL);
+ if (!pp)
+ goto out_fds;
+ }
pp->next=NULL;
- pp->len = (i>POLLFD_PER_PAGE?POLLFD_PER_PAGE:i);
+ pp->len = num;
if (head == NULL)
head = pp;
else
walk = pp;
if (copy_from_user(pp->entries, ufds + nfds-i,
- sizeof(struct pollfd)*pp->len)) {
+ sizeof(struct pollfd)*num)) {
err = -EFAULT;
goto out_fds;
}
walk = head;
while(walk!=NULL) {
struct poll_list *pp = walk->next;
- kfree(walk);
+ if (walk != stack_pp)
+ kfree(walk);
walk = pp;
}
poll_freewait(&table);
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)
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);
git.openpandora.org / pandora-kernel.git / blobdiff