MFC Alexander Motin's direct dispatch, multi-queue, and finer-grained

locking support for CAM

r256826:
Fix several target mode SIMs to not blindly clear ccb_h.flags field of
ATIO CCBs.  Not all CCB flags there belong to them.

r256836:
Remove hard limit on number of BIOs handled with one ATA TRIM request.

r256843:
Merge CAM locking changes from the projects/camlock branch to radically
reduce lock congestion and improve SMP scalability of the SCSI/ATA stack,
preparing the ground for the coming next GEOM direct dispatch support.

r256888:
Unconditionally acquire periph reference on CCB allocation failure.

r256895:
Fix memory and references leak due to unfreed path.

r256960:
Move CAM_UNQUEUED_INDEX setting to the last moment and under the periph lock.
This fixes race condition with cam_periph_ccbwait(), causing use-after-free.

r256975:
Minor (mostly cosmetical) addition to r256960.

r257054:
Some microoptimizations for da and ada drivers:
 - Replace ordered_tag_count counter with single flag;
 - From da remove outstanding_cmds counter, duplicating pending_ccbs list;
 - From da_softc remove unused links field.

r257482:
Fix lock recursion, triggered by `smartctl -a /dev/adaX`.

r257501:
Make getenv_*() functions and respectively TUNABLE_*_FETCH() macros not
allocate memory and so not require sleepable environment.  getenv() has
already used on-stack temporary storage, so just use it more rationally.
getenv_string() receives buffer as argument, so don't need another one.

r257914:
Some CAM locks polishing:
 - Fix LOR and possible lock recursion when handling high-power commands.
Introduce new lock to protect left power quota and list of frozen devices.
 - Correct locking around xpt periph creation.
 - Remove seems never used XPT_FLAG_OPEN xpt periph flag.

Again, Netflix assisted with testing the merge, but all of the credit goes
to Alexander and iX Systems.

Submitted by:	mav
Sponsored by:	iX Systems

1 files changed, 19 insertions, 27 deletions

diff --git a/sys/kern/kern_environment.c b/sys/kern/kern_environment.c
index e89b3f7..ff453cb 100644
--- a/sys/kern/kern_environment.c
+++ b/sys/kern/kern_environment.c
@@ -315,20 +315,12 @@ char *
 getenv(const char *name)
 {
 	char buf[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1];
-	char *ret, *cp;
-	int len;
+	char *ret;
 
 	if (dynamic_kenv) {
-		mtx_lock(&kenv_lock);
-		cp = _getenv_dynamic(name, NULL);
-		if (cp != NULL) {
-			strcpy(buf, cp);
-			mtx_unlock(&kenv_lock);
-			len = strlen(buf) + 1;
-			ret = malloc(len, M_KENV, M_WAITOK);
-			strcpy(ret, buf);
+		if (getenv_string(name, buf, sizeof(buf))) {
+			ret = strdup(buf, M_KENV);
 		} else {
-			mtx_unlock(&kenv_lock);
 			ret = NULL;
 			WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
 			    "getenv");
@@ -458,15 +450,20 @@ unsetenv(const char *name)
 int
 getenv_string(const char *name, char *data, int size)
 {
-	char *tmp;
+	char *cp;
 
-	tmp = getenv(name);
-	if (tmp != NULL) {
-		strlcpy(data, tmp, size);
-		freeenv(tmp);
-		return (1);
-	} else
-		return (0);
+	if (dynamic_kenv) {
+		mtx_lock(&kenv_lock);
+		cp = _getenv_dynamic(name, NULL);
+		if (cp != NULL)
+			strlcpy(data, cp, size);
+		mtx_unlock(&kenv_lock);
+	} else {
+		cp = _getenv_static(name);
+		if (cp != NULL)
+			strlcpy(data, cp, size);
+	}
+	return (cp != NULL);
 }
 
 /*
@@ -535,18 +532,15 @@ getenv_ulong(const char *name, unsigned long *data)
 int
 getenv_quad(const char *name, quad_t *data)
 {
-	char	*value;
+	char	value[KENV_MNAMELEN + 1 + KENV_MVALLEN + 1];
 	char	*vtp;
 	quad_t	iv;
 
-	value = getenv(name);
-	if (value == NULL)
+	if (!getenv_string(name, value, sizeof(value)))
 		return (0);
 	iv = strtoq(value, &vtp, 0);
-	if (vtp == value || (vtp[0] != '\0' && vtp[1] != '\0')) {
-		freeenv(value);
+	if (vtp == value || (vtp[0] != '\0' && vtp[1] != '\0'))
 		return (0);
-	}
 	switch (vtp[0]) {
 	case 't': case 'T':
 		iv *= 1024;
@@ -559,11 +553,9 @@ getenv_quad(const char *name, quad_t *data)
 	case '\0':
 		break;
 	default:
-		freeenv(value);
 		return (0);
 	}
 	*data = iv;
-	freeenv(value);
 	return (1);
 }