MFC 303881: Reliably return PCI_GETCONF_LAST_DEVICE from PCIOCGETCONF.

Previously the loop in PCIIOCGETCONF would terminate as soon as it
found enough matches.  Now it will continue iterating through the
PCI device list and only terminate if it finds another matching device
for which it has no room to store a conf structure.  This means that
PCI_GETCONF_LAST_DEVICE is reliably returned when the number of
matching devices is equal to the number of slots in the matches
buffer.  For example, if a program requests the conf structure for a
single PCI function with a specified domain/bus/slot/function it will
now get PCI_GETCONF_LAST_DEVICE instead of PCI_GETCONF_MORE_DEVS.

While here, simplify the loop conditional a bit more by explicitly
breaking out of the loop if copyout() fails and removing a redundant
i < pci_numdevs check.

Sponsored by:	Chelsio Communications

1 files changed, 7 insertions, 7 deletions

diff --git a/sys/dev/pci/pci_user.c b/sys/dev/pci/pci_user.c
index f5a921a..dba76d1 100644
--- a/sys/dev/pci/pci_user.c
+++ b/sys/dev/pci/pci_user.c
@@ -708,10 +708,9 @@ pci_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int flag, struct thread *t
 		 * Go through the list of devices and copy out the devices
 		 * that match the user's criteria.
 		 */
-		for (cio->num_matches = 0, error = 0, i = 0,
+		for (cio->num_matches = 0, i = 0,
 				 dinfo = STAILQ_FIRST(devlist_head);
-		     (dinfo != NULL) && (cio->num_matches < ionum) &&
-				 (error == 0) && (i < pci_numdevs);
+		     dinfo != NULL;
 		     dinfo = STAILQ_NEXT(dinfo, pci_links), i++) {
 
 			if (i < cio->offset)
@@ -833,11 +832,12 @@ pci_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int flag, struct thread *t
 				} else
 #endif /* PRE7_COMPAT */
 					confdata = &dinfo->conf;
-				/* Only if we can copy it out do we count it. */
-				if (!(error = copyout(confdata,
+				error = copyout(confdata,
 				    (caddr_t)cio->matches +
-				    confsz * cio->num_matches, confsz)))
-					cio->num_matches++;
+				    confsz * cio->num_matches, confsz);
+				if (error)
+					break;
+				cio->num_matches++;
 			}
 		}