Add sigmask parameter to io_uring_enter

Update liburing and io_uring_enter.2 to match the kernel.

Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

man/io_uring_enter.2

@@ -13,7 +13,8 @@ io_uring_enter \- initiate and/or complete asynchronous I/O
 .BR "#include <linux/io_uring.h>"
 .PP
 .BI "int io_uring_enter(unsigned int " fd ", unsigned int " to_submit ,
-.BI "                   unsigned int " min_complete ", unsigned int " flags)
+.BI "                   unsigned int " min_complete ", unsigned int " flags ,
+.BI "                   sigset_t *" sig ", size_t " sigsz)
 .fi
 .PP
 .SH DESCRIPTION
@@ -52,6 +53,48 @@ flag in
 as for IRQ driven I/O, the application can just check the completion
 queue without entering the kernel.
 
+.I sig
+is a pointer to a signal mask (see
+.BR sigprocmask (2));
+.I sigsz
+is the size of the
+.I sig
+argument.  If
+.I sig
+is not NULL,
+.BR io_uring_enter ()
+first replaces the current signal mask by the one pointed to by
+.I sig,
+then waits for events to become available in the completion queue, and
+then restores the original signal mask.  The following
+.BI io_uring_enter ()
+call:
+.PP
+.in +4n
+.EX
+ret = io_uring_enter(fd, 0, 1,
+            IORING_ENTER_GETEVENTS, &sig, sigsz);
+.EE
+.in
+.PP
+is equivalent to
+.I atomically
+executing the following calls:
+.PP
+.in +4n
+.EX
+pthread_sigmask(SIG_SETMASK, &sig, &orig);
+ret = io_uring_enter(fd, 0, 1, IORING_ENTER_GETEVENTS, NULL, 0);
+pthread_sigmask(SIG_SETMASK, &orig, NULL);
+.EE
+.in
+.PP
+See the description of
+.BR pselect (2)
+for an explanation of why the
+.I sig
+parameter is necessary.
+
 Submission queue entries are represented using the following data
 structure:
 .PP

src/liburing.h

@@ -2,6 +2,7 @@
 #define LIB_URING_H
 
 #include <sys/uio.h>
+#include <signal.h>
 #include "compat.h"
 #include "io_uring.h"
 
@@ -46,7 +47,7 @@ struct io_uring {
  */
 extern int io_uring_setup(unsigned entries, struct io_uring_params *p);
 extern int io_uring_enter(unsigned fd, unsigned to_submit,
-	unsigned min_complete, unsigned flags);
+	unsigned min_complete, unsigned flags, sigset_t *sig, size_t sigsz);
 extern int io_uring_register(int fd, unsigned int opcode, void *arg,
 	unsigned int nr_args);
 

src/queue.c

@@ -29,7 +29,7 @@ static int __io_uring_get_completion(struct io_uring *ring,
 		if (!wait)
 			break;
 		ret = io_uring_enter(ring->ring_fd, 0, 1,
-					IORING_ENTER_GETEVENTS);
+					IORING_ENTER_GETEVENTS, NULL, _NSIG / 8);
 		if (ret < 0)
 			return -errno;
 	} while (1);
@@ -112,7 +112,7 @@ int io_uring_submit(struct io_uring *ring)
 
 submit:
 	return io_uring_enter(ring->ring_fd, submitted, 0,
-				IORING_ENTER_GETEVENTS);
+				IORING_ENTER_GETEVENTS, NULL, _NSIG / 8);
 }
 
 /*

src/syscall.c

@@ -33,8 +33,8 @@ int io_uring_setup(unsigned int entries, struct io_uring_params *p)
 }
 
 int io_uring_enter(int fd, unsigned int to_submit, unsigned int min_complete,
-		   unsigned int flags)
+		   unsigned int flags, sigset_t *sig, size_t sigsz)
 {
 	return syscall(__NR_sys_io_uring_enter, fd, to_submit, min_complete,
-			flags, NULL, 0);
+			flags, sig, sigsz);
 }