diff options
Diffstat (limited to 'fs')
-rw-r--r-- | fs/select.c | 106 |
1 files changed, 64 insertions, 42 deletions
diff --git a/fs/select.c b/fs/select.c index 1815a57d225..d8b4f0722b8 100644 --- a/fs/select.c +++ b/fs/select.c @@ -29,12 +29,6 @@ #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) @@ -284,16 +294,6 @@ 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 @@ -312,6 +312,8 @@ static int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp, char *bits; int ret, size, max_fdset; struct fdtable *fdt; + /* Allocate small arguments on the stack to save memory and be faster */ + char stack_fds[SELECT_STACK_ALLOC]; ret = -EINVAL; if (n < 0) @@ -332,7 +334,10 @@ static int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp, */ ret = -ENOMEM; size = FDS_BYTES(n); - bits = select_bits_alloc(size); + if (6*size < SELECT_STACK_ALLOC) + bits = stack_fds; + else + bits = kmalloc(6 * size, GFP_KERNEL); if (!bits) goto out_nofds; fds.in = (unsigned long *) bits; @@ -367,7 +372,8 @@ 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; } @@ -619,6 +625,9 @@ 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; @@ -628,6 +637,9 @@ 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 */ + char stack_pps[POLL_STACK_ALLOC]; + struct poll_list *stack_pp = NULL; /* Do a sanity check on nfds ... */ rcu_read_lock(); @@ -645,14 +657,23 @@ 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 @@ -660,7 +681,7 @@ 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; } @@ -689,7 +710,8 @@ 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); |