File 0001-drmgr-don-t-open-sysfs-file-for-each-command.patch of Package powerpc-utils.20109

From 8b03106e699de1f19b8842ebbb5a91b9a6e5fa6d Mon Sep 17 00:00:00 2001
From: Laurent Dufour <ldufour@linux.ibm.com>
Date: Tue, 24 Nov 2020 19:28:48 +0100
Subject: [PATCH 1/4] drmgr: don't open sysfs file for each command

The new do_kernel_dlpar_common() API will be used in later commit to remove
by DRC Index LMB per LMB. This will avoiding opennig and closing the fd
each time.

The fd closing will now be done at the process exit time.

In addition add an optinal parameter to silently ignore some error.

Also, change the log level of the "success" message to debug to match
the previous one saying "Trying.."

Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com>
---
 src/drmgr/common.c | 30 +++++++++++++++++-------------
 src/drmgr/dr.h     |  6 +++++-
 2 files changed, 22 insertions(+), 14 deletions(-)

diff --git a/src/drmgr/common.c b/src/drmgr/common.c
index 5e8135bcf77e..341777250feb 100644
--- a/src/drmgr/common.c
+++ b/src/drmgr/common.c
@@ -1462,39 +1462,43 @@ int kernel_dlpar_exists(void)
 }
 
 /**
- * do_kernel_dlpar
+ * do_kernel_dlpar_common
  * @brief Use the in-kernel dlpar capabilities to perform the requested
  *        dlpar operation.
  *
  * @param cmd command string to write to sysfs
+ * @silent_error if not 0, error is not reported, it's up to the caller
  * @returns 0 on success, !0 otherwise
  */
-int do_kernel_dlpar(const char *cmd, int cmdlen)
+int do_kernel_dlpar_common(const char *cmd, int cmdlen, int silent_error)
 {
-	int fd, rc;
-	int my_errno;
+	static int fd = -1;
+	int rc;
 
 	say(DEBUG, "Initiating kernel DLPAR \"%s\"\n", cmd);
 
 	/* write to file */
-	fd = open(SYSFS_DLPAR_FILE, O_WRONLY);
-	if (fd <= 0) {
-		say(ERROR, "Could not open %s to initiate DLPAR request\n",
-		    SYSFS_DLPAR_FILE);
-		return -1;
+	if (fd == -1) {
+		fd = open(SYSFS_DLPAR_FILE, O_WRONLY);
+		if (fd < 0) {
+			say(ERROR,
+			    "Could not open %s to initiate DLPAR request\n",
+			    SYSFS_DLPAR_FILE);
+			return -1;
+		}
 	}
 
 	rc = write(fd, cmd, cmdlen);
-	my_errno = errno;
-	close(fd);
 	if (rc <= 0) {
+		if (silent_error)
+			return (errno == 0) ? -1 : -errno;
 		/* write does not set errno for rc == 0 */
 		say(ERROR, "Failed to write to %s: %s\n", SYSFS_DLPAR_FILE,
-		    (rc == 0) ? "wrote 0 bytes" : strerror(my_errno));
+		    (rc == 0) ? "wrote 0 bytes" : strerror(errno));
 		return -1;
 	}
 
-	say(INFO, "Success\n");
+	say(DEBUG, "Success\n");
 	return 0;
 }
 
diff --git a/src/drmgr/dr.h b/src/drmgr/dr.h
index f171bfea73c3..ffbcfdb15cc0 100644
--- a/src/drmgr/dr.h
+++ b/src/drmgr/dr.h
@@ -172,5 +172,9 @@ enum drc_type to_drc_type(const char *);
 int handle_prrn(void);
 
 int kernel_dlpar_exists(void);
-int do_kernel_dlpar(const char *, int);
+int do_kernel_dlpar_common(const char *, int, int);
+static inline int do_kernel_dlpar(const char *cmd, int len)
+{
+	return do_kernel_dlpar_common(cmd, len, 0);
+}
 #endif
-- 
2.31.1