linux-kernel - [PATCH 1/2] powerpc/fadump: return 0 on re-registration

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Message-Id: <20170626140601.7106-1-msuchanek@suse.de>
Date:   Mon, 26 Jun 2017 16:06:00 +0200
From:   Michal Suchanek <msuchanek@...e.de>
To:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>,
        Hari Bathini <hbathini@...ux.vnet.ibm.com>,
        Mahesh Salgaonkar <mahesh@...ux.vnet.ibm.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Michal Suchanek <msuchanek@...e.de>,
        Colin Ian King <colin.king@...onical.com>,
        linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org
Subject: [PATCH 1/2] powerpc/fadump: return 0 on re-registration

When fadump is already registered return success.

Currently EEXIST is returned which is difficult to handle race-free in
userspace when shell scripts are used. If multiple writers are trying to
write '1' there is no difference in whichever succeeds so just return 0
to all.

Signed-off-by: Michal Suchanek <msuchanek@...e.de>
---
 arch/powerpc/kernel/fadump.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
index 436aedf195ab..5a7355381dac 100644
--- a/arch/powerpc/kernel/fadump.c
+++ b/arch/powerpc/kernel/fadump.c
@@ -1214,7 +1214,6 @@ static ssize_t fadump_register_store(struct kobject *kobj,
 		break;
 	case '1':
 		if (fw_dump.dump_registered == 1) {
-			ret = -EEXIST;
 			goto unlock_out;
 		}
 		/* Register Firmware-assisted dump */
-- 
2.10.2