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| author | Heiko Carstens <heiko.carstens@de.ibm.com> | 2006-12-04 15:40:30 +0100 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2006-12-04 15:40:30 +0100 |
| commit | 740b5706b9c4b3767f597b3ea76654c6f2a800b2 (patch) | |
| tree | 370dc09ec8f3abaecc742003ed9d28eecf636c3b /arch/s390/kernel/cpcmd.c | |
| parent | a1a392f0b4f27604811bf8aa8d7636b3b4bc3803 (diff) | |
| download | linux-740b5706b9c4b3767f597b3ea76654c6f2a800b2.tar.bz2 | |
[S390] cpcmd <-> __cpcmd calling issues
In case of reipl cpcmd gets called when all other cpus are not running
anymore. To prevent deadlocks change __cpcmd so that it doesn't take
any locks and call cpcmd or __cpcmd, whatever is correct in the current
context.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/kernel/cpcmd.c')
| -rw-r--r-- | arch/s390/kernel/cpcmd.c | 18 |
1 files changed, 11 insertions, 7 deletions
diff --git a/arch/s390/kernel/cpcmd.c b/arch/s390/kernel/cpcmd.c index 1eae74e72f95..a5972f1541fe 100644 --- a/arch/s390/kernel/cpcmd.c +++ b/arch/s390/kernel/cpcmd.c @@ -21,14 +21,15 @@ static DEFINE_SPINLOCK(cpcmd_lock); static char cpcmd_buf[241]; /* - * the caller of __cpcmd has to ensure that the response buffer is below 2 GB + * __cpcmd has some restrictions over cpcmd + * - the response buffer must reside below 2GB (if any) + * - __cpcmd is unlocked and therefore not SMP-safe */ int __cpcmd(const char *cmd, char *response, int rlen, int *response_code) { - unsigned long flags, cmdlen; + unsigned cmdlen; int return_code, return_len; - spin_lock_irqsave(&cpcmd_lock, flags); cmdlen = strlen(cmd); BUG_ON(cmdlen > 240); memcpy(cpcmd_buf, cmd, cmdlen); @@ -74,7 +75,6 @@ int __cpcmd(const char *cmd, char *response, int rlen, int *response_code) : "+d" (reg3) : "d" (reg2) : "cc"); return_code = (int) reg3; } - spin_unlock_irqrestore(&cpcmd_lock, flags); if (response_code != NULL) *response_code = return_code; return return_len; @@ -82,15 +82,18 @@ int __cpcmd(const char *cmd, char *response, int rlen, int *response_code) EXPORT_SYMBOL(__cpcmd); -#ifdef CONFIG_64BIT int cpcmd(const char *cmd, char *response, int rlen, int *response_code) { char *lowbuf; int len; + unsigned long flags; if ((rlen == 0) || (response == NULL) - || !((unsigned long)response >> 31)) + || !((unsigned long)response >> 31)) { + spin_lock_irqsave(&cpcmd_lock, flags); len = __cpcmd(cmd, response, rlen, response_code); + spin_unlock_irqrestore(&cpcmd_lock, flags); + } else { lowbuf = kmalloc(rlen, GFP_KERNEL | GFP_DMA); if (!lowbuf) { @@ -98,7 +101,9 @@ int cpcmd(const char *cmd, char *response, int rlen, int *response_code) "cpcmd: could not allocate response buffer\n"); return -ENOMEM; } + spin_lock_irqsave(&cpcmd_lock, flags); len = __cpcmd(cmd, lowbuf, rlen, response_code); + spin_unlock_irqrestore(&cpcmd_lock, flags); memcpy(response, lowbuf, rlen); kfree(lowbuf); } @@ -106,4 +111,3 @@ int cpcmd(const char *cmd, char *response, int rlen, int *response_code) } EXPORT_SYMBOL(cpcmd); -#endif /* CONFIG_64BIT */ |