Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next

[cascardo/linux.git] / fs / select.c

diff --git a/fs/select.c b/fs/select.c
index 6b14dc7..f9f49c4 100644 (file)
--- a/fs/select.c
+++ b/fs/select.c
@@ -28,6 +28,7 @@
 #include <linux/hrtimer.h>
 #include <linux/sched/rt.h>
 #include <linux/freezer.h>
+#include <net/ll_poll.h>
 
 #include <asm/uaccess.h>
 
@@ -386,9 +387,10 @@ get_max:
 #define POLLEX_SET (POLLPRI)
 
 static inline void wait_key_set(poll_table *wait, unsigned long in,
-                               unsigned long out, unsigned long bit)
+                               unsigned long out, unsigned long bit,
+                               unsigned int ll_flag)
 {
-       wait->_key = POLLEX_SET;
+       wait->_key = POLLEX_SET | ll_flag;
        if (in & bit)
                wait->_key |= POLLIN_SET;
        if (out & bit)
@@ -402,6 +404,8 @@ int do_select(int n, fd_set_bits *fds, struct timespec *end_time)
        poll_table *wait;
        int retval, i, timed_out = 0;
        unsigned long slack = 0;
+       unsigned int busy_flag = net_busy_loop_on() ? POLL_BUSY_LOOP : 0;
+       unsigned long busy_end = 0;
 
        rcu_read_lock();
        retval = max_select_fd(n, fds);
@@ -424,6 +428,7 @@ int do_select(int n, fd_set_bits *fds, struct timespec *end_time)
        retval = 0;
        for (;;) {
                unsigned long *rinp, *routp, *rexp, *inp, *outp, *exp;
+               bool can_busy_loop = false;
 
                inp = fds->in; outp = fds->out; exp = fds->ex;
                rinp = fds->res_in; routp = fds->res_out; rexp = fds->res_ex;
@@ -451,7 +456,8 @@ int do_select(int n, fd_set_bits *fds, struct timespec *end_time)
                                        f_op = f.file->f_op;
                                        mask = DEFAULT_POLLMASK;
                                        if (f_op && f_op->poll) {
-                                               wait_key_set(wait, in, out, bit);
+                                               wait_key_set(wait, in, out,
+                                                            bit, busy_flag);
                                                mask = (*f_op->poll)(f.file, wait);
                                        }
                                        fdput(f);
@@ -470,6 +476,18 @@ int do_select(int n, fd_set_bits *fds, struct timespec *end_time)
                                                retval++;
                                                wait->_qproc = NULL;
                                        }
+                                       /* got something, stop busy polling */
+                                       if (retval) {
+                                               can_busy_loop = false;
+                                               busy_flag = 0;
+
+                                       /*
+                                        * only remember a returned
+                                        * POLL_BUSY_LOOP if we asked for it
+                                        */
+                                       } else if (busy_flag & mask)
+                                               can_busy_loop = true;
+
                                }
                        }
                        if (res_in)
@@ -488,6 +506,17 @@ int do_select(int n, fd_set_bits *fds, struct timespec *end_time)
                        break;
                }
 
+               /* only if found POLL_BUSY_LOOP sockets && not out of time */
+               if (can_busy_loop && !need_resched()) {
+                       if (!busy_end) {
+                               busy_end = busy_loop_end_time();
+                               continue;
+                       }
+                       if (!busy_loop_timeout(busy_end))
+                               continue;
+               }
+               busy_flag = 0;
+
                /*
                 * If this is the first loop and we have a timeout
                 * given, then we convert to ktime_t and set the to
@@ -719,7 +748,9 @@ struct poll_list {
  * pwait poll_table will be used by the fd-provided poll handler for waiting,
  * if pwait->_qproc is non-NULL.
  */
-static inline unsigned int do_pollfd(struct pollfd *pollfd, poll_table *pwait)
+static inline unsigned int do_pollfd(struct pollfd *pollfd, poll_table *pwait,
+                                    bool *can_busy_poll,
+                                    unsigned int busy_flag)
 {
        unsigned int mask;
        int fd;
@@ -733,7 +764,10 @@ static inline unsigned int do_pollfd(struct pollfd *pollfd, poll_table *pwait)
                        mask = DEFAULT_POLLMASK;
                        if (f.file->f_op && f.file->f_op->poll) {
                                pwait->_key = pollfd->events|POLLERR|POLLHUP;
+                               pwait->_key |= busy_flag;
                                mask = f.file->f_op->poll(f.file, pwait);
+                               if (mask & busy_flag)
+                                       *can_busy_poll = true;
                        }
                        /* Mask out unneeded events. */
                        mask &= pollfd->events | POLLERR | POLLHUP;
@@ -752,6 +786,8 @@ static int do_poll(unsigned int nfds,  struct poll_list *list,
        ktime_t expire, *to = NULL;
        int timed_out = 0, count = 0;
        unsigned long slack = 0;
+       unsigned int busy_flag = net_busy_loop_on() ? POLL_BUSY_LOOP : 0;
+       unsigned long busy_end = 0;
 
        /* Optimise the no-wait case */
        if (end_time && !end_time->tv_sec && !end_time->tv_nsec) {
@@ -764,6 +800,7 @@ static int do_poll(unsigned int nfds,  struct poll_list *list,
 
        for (;;) {
                struct poll_list *walk;
+               bool can_busy_loop = false;
 
                for (walk = list; walk != NULL; walk = walk->next) {
                        struct pollfd * pfd, * pfd_end;
@@ -778,9 +815,13 @@ static int do_poll(unsigned int nfds,  struct poll_list *list,
                                 * this. They'll get immediately deregistered
                                 * when we break out and return.
                                 */
-                               if (do_pollfd(pfd, pt)) {
+                               if (do_pollfd(pfd, pt, &can_busy_loop,
+                                             busy_flag)) {
                                        count++;
                                        pt->_qproc = NULL;
+                                       /* found something, stop busy polling */
+                                       busy_flag = 0;
+                                       can_busy_loop = false;
                                }
                        }
                }
@@ -797,6 +838,17 @@ static int do_poll(unsigned int nfds,  struct poll_list *list,
                if (count || timed_out)
                        break;
 
+               /* only if found POLL_BUSY_LOOP sockets && not out of time */
+               if (can_busy_loop && !need_resched()) {
+                       if (!busy_end) {
+                               busy_end = busy_loop_end_time();
+                               continue;
+                       }
+                       if (!busy_loop_timeout(busy_end))
+                               continue;
+               }
+               busy_flag = 0;
+
                /*
                 * If this is the first loop and we have a timeout
                 * given, then we convert to ktime_t and set the to