Pull trivial1 into release branch
[pandora-kernel.git] / fs / select.c
index bc60a3e..a8109ba 100644 (file)
 #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;
@@ -64,13 +58,23 @@ void poll_initwait(struct poll_wqueues *pwq)
        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;
@@ -78,8 +82,7 @@ void poll_freewait(struct poll_wqueues *pwq)
                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;
@@ -89,12 +92,14 @@ void poll_freewait(struct poll_wqueues *pwq)
 
 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;
 
@@ -102,7 +107,7 @@ static void __pollwait(struct file *filp, wait_queue_head_t *wait_address,
                if (!new_table) {
                        p->error = -ENOMEM;
                        __set_current_state(TASK_RUNNING);
-                       return;
+                       return NULL;
                }
                new_table->entry = new_table->entries;
                new_table->next = table;
@@ -110,16 +115,21 @@ static void __pollwait(struct file *filp, wait_queue_head_t *wait_address,
                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)
@@ -210,7 +220,7 @@ int do_select(int n, fd_set_bits *fds, s64 *timeout)
                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++;
@@ -221,17 +231,18 @@ int do_select(int n, fd_set_bits *fds, s64 *timeout)
                        }
 
                        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++;
@@ -284,16 +295,6 @@ int do_select(int n, fd_set_bits *fds, s64 *timeout)
        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
@@ -309,9 +310,12 @@ static int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp,
                           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)
@@ -330,17 +334,21 @@ static int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp,
         * 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)) ||
@@ -367,7 +375,8 @@ static int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp,
                ret = -EFAULT;
 
 out:
-       select_bits_free(bits, size);
+       if (bits != stack_fds)
+               kfree(bits);
 out_nofds:
        return ret;
 }
@@ -398,11 +407,15 @@ asmlinkage long sys_select(int n, fd_set __user *inp, fd_set __user *outp,
        ret = core_sys_select(n, inp, outp, exp, &timeout);
 
        if (tvp) {
+               struct timeval rtv;
+
                if (current->personality & STICKY_TIMEOUTS)
                        goto sticky;
-               tv.tv_usec = jiffies_to_usecs(do_div((*(u64*)&timeout), HZ));
-               tv.tv_sec = timeout;
-               if (copy_to_user(tvp, &tv, sizeof(tv))) {
+               rtv.tv_usec = jiffies_to_usecs(do_div((*(u64*)&timeout), HZ));
+               rtv.tv_sec = timeout;
+               if (timeval_compare(&rtv, &tv) >= 0)
+                       rtv = tv;
+               if (copy_to_user(tvp, &rtv, sizeof(rtv))) {
 sticky:
                        /*
                         * If an application puts its timeval in read-only
@@ -460,11 +473,16 @@ asmlinkage long sys_pselect7(int n, fd_set __user *inp, fd_set __user *outp,
        ret = core_sys_select(n, inp, outp, exp, &timeout);
 
        if (tsp) {
+               struct timespec rts;
+
                if (current->personality & STICKY_TIMEOUTS)
                        goto sticky;
-               ts.tv_nsec = jiffies_to_usecs(do_div((*(u64*)&timeout), HZ)) * 1000;
-               ts.tv_sec = timeout;
-               if (copy_to_user(tsp, &ts, sizeof(ts))) {
+               rts.tv_nsec = jiffies_to_usecs(do_div((*(u64*)&timeout), HZ)) *
+                                               1000;
+               rts.tv_sec = timeout;
+               if (timespec_compare(&rts, &ts) >= 0)
+                       rts = ts;
+               if (copy_to_user(tsp, &rts, sizeof(rts))) {
 sticky:
                        /*
                         * If an application puts its timeval in read-only
@@ -542,14 +560,15 @@ static void do_pollfd(unsigned int num, struct pollfd * fdpage,
                fdp = fdpage+i;
                fd = fdp->fd;
                if (fd >= 0) {
-                       struct file * file = fget(fd);
+                       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(file);
+                               fput_light(file, fput_needed);
                        }
                        if (mask) {
                                *pwait = NULL;
@@ -610,6 +629,9 @@ static int do_poll(unsigned int nfds,  struct poll_list *list,
        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;
@@ -619,6 +641,11 @@ int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds, s64 *timeout)
        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();
@@ -636,14 +663,23 @@ int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds, s64 *timeout)
        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
@@ -651,7 +687,7 @@ int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds, s64 *timeout)
 
                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;
                }
@@ -680,7 +716,8 @@ 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);
@@ -758,12 +795,17 @@ asmlinkage long sys_ppoll(struct pollfd __user *ufds, unsigned int nfds,
                sigprocmask(SIG_SETMASK, &sigsaved, NULL);
 
        if (tsp && timeout >= 0) {
+               struct timespec rts;
+
                if (current->personality & STICKY_TIMEOUTS)
                        goto sticky;
                /* Yes, we know it's actually an s64, but it's also positive. */
-               ts.tv_nsec = jiffies_to_usecs(do_div((*(u64*)&timeout), HZ)) * 1000;
-               ts.tv_sec = timeout;
-               if (copy_to_user(tsp, &ts, sizeof(ts))) {
+               rts.tv_nsec = jiffies_to_usecs(do_div((*(u64*)&timeout), HZ)) *
+                                               1000;
+               rts.tv_sec = timeout;
+               if (timespec_compare(&rts, &ts) >= 0)
+                       rts = ts;
+               if (copy_to_user(tsp, &rts, sizeof(rts))) {
                sticky:
                        /*
                         * If an application puts its timeval in read-only