linux-4.4.1/do_sys_poll() の変更点

• 追加された行はこの色です。
• 削除された行はこの色です。
• linux-4.4.1/do_sys_poll() へ行く。
• linux-4.4.1/do_sys_poll() の差分を削除

*参照元 [#bbe269fe]
#backlinks

*説明 [#ae42a17c]
-パス: [[linux-4.4.1/fs/select.c]]

-FIXME: これは何？
--説明


**引数 [#e9cc0de8]
-struct pollfd __user *ufds
--
--[[linux-4.4.1/pollfd]]
-unsigned int nfds
--
-struct timespec *end_time
--
--[[linux-4.4.1/timespec]]


**返り値 [#p0149fe4]
-int
--


**参考 [#e8c52795]


*実装 [#e45b950b]
 int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds,
 		struct timespec *end_time)
 {
 	struct poll_wqueues table;
  	int err = -EFAULT, fdcount, len, size;
 	/* 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 *const head = (struct poll_list *)stack_pps;
  	struct poll_list *walk = head;
  	unsigned long todo = nfds;
 
-
--[[linux-4.4.1/poll_wqueues]]
--[[linux-4.4.1/POLL_STACK_ALLOC]]
--[[linux-4.4.1/poll_list]]

 	if (nfds > rlimit(RLIMIT_NOFILE))
 		return -EINVAL;
 
-
--[[linux-4.4.1/rlimit()]]

 	len = min_t(unsigned int, nfds, N_STACK_PPS);
-
--[[linux-4.4.1/min_t()]]

 	for (;;) {
 		walk->next = NULL;
 		walk->len = len;
 		if (!len)
 			break;
 
 		if (copy_from_user(walk->entries, ufds + nfds-todo,
 					sizeof(struct pollfd) * walk->len))
 			goto out_fds;
 
-
--[[linux-4.4.1/copy_from_user()]]

 		todo -= walk->len;
 		if (!todo)
 			break;
 
 		len = min(todo, POLLFD_PER_PAGE);
 		size = sizeof(struct poll_list) + sizeof(struct pollfd) * len;
 		walk = walk->next = kmalloc(size, GFP_KERNEL);
 		if (!walk) {
 			err = -ENOMEM;
 			goto out_fds;
 		}
-
--[[linux-4.4.1/kmalloc()]]

 	}
 
 	poll_initwait(&table);
 	fdcount = do_poll(nfds, head, &table, end_time);
 	poll_freewait(&table);
 
-
--[[linux-4.4.1/poll_initwait()]]
--[[linux-4.4.1/do_poll()]]
--[[linux-4.4.1/poll_freewait()]]

 	for (walk = head; walk; walk = walk->next) {
 		struct pollfd *fds = walk->entries;
 		int j;
 
 		for (j = 0; j < walk->len; j++, ufds++)
 			if (__put_user(fds[j].revents, &ufds->revents))
 				goto out_fds;
   	}
 
-
--[[linux-4.4.1/pollfd]]
--[[linux-4.4.1/__put_user()]]

 	err = fdcount;
 out_fds:
 	walk = head->next;
 	while (walk) {
 		struct poll_list *pos = walk;
 		walk = walk->next;
 		kfree(pos);
 	}
 
-
--[[linux-4.4.1/kfree()]]

 	return err;
 }


*コメント [#u2b590ef]