svn commit: r338542 - head/sys/dev/random

[Xin LI]

Author: delphij
Date: Sun Sep  9 17:12:31 2018
New Revision: 338542
URL: https://svnweb.freebsd.org/changeset/base/338542

Log:
  random(4): Squash non-error timeout codes from tsleep(9).
  
  In both scenarios a timeout (EWOULDBLOCK) is considered as a
  normal condition and the error should not pop up to upper layers.
  
  PR:		231181
  Submitted by:	cem
  Reported by:	lev
  Reviewed by:	vangyzen, markm, delphij
  Approved by:	re (kib)
  Approved by:	secteam (delphij)
  Differential Revision:	https://reviews.freebsd.org/D17049

Modified:
  head/sys/dev/random/randomdev.c

Modified: head/sys/dev/random/randomdev.c
==============================================================================
--- head/sys/dev/random/randomdev.c	Sun Sep  9 07:20:15 2018	(r338541)
+++ head/sys/dev/random/randomdev.c	Sun Sep  9 17:12:31 2018	(r338542)
@@ -156,6 +156,10 @@ READ_RANDOM_UIO(struct uio *uio, bool nonblock)
 		error = tsleep(&random_alg_context, PCATCH, "randseed", hz/10);
 		if (error == ERESTART || error == EINTR)
 			break;
+		/* Squash tsleep timeout condition */
+		if (error == EWOULDBLOCK)
+			error = 0;
+		KASSERT(error == 0, ("unexpected tsleep error %d", error));
 	}
 	if (error == 0) {
 		read_rate_increment((uio->uio_resid + sizeof(uint32_t))/sizeof(uint32_t));
@@ -184,9 +188,13 @@ READ_RANDOM_UIO(struct uio *uio, bool nonblock)
 			 * uninterruptible syscalls.
 			 */
 			if (error == 0 && uio->uio_resid != 0 &&
-			    total_read % sigchk_period == 0)
+			    total_read % sigchk_period == 0) {
 				error = tsleep_sbt(&random_alg_context, PCATCH,
 				    "randrd", SBT_1NS, 0, C_HARDCLOCK);
+				/* Squash tsleep timeout condition */
+				if (error == EWOULDBLOCK)
+					error = 0;
+			}
 		}
 		if (error == ERESTART || error == EINTR)
 			error = 0;