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| author | Akash Goel <akash.goel@intel.com> | 2016-09-02 21:47:38 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2016-09-06 18:30:19 +0200 |
| commit | 017c59c042d01fc84cae7a8ea475861e702c77ab (patch) | |
| tree | ee665d166dff1e47e5815fd74130e67c23ba29bf /include/linux/relay.h | |
| parent | ee1e714b94521b0bb27b04dfd1728ec51b19d4f0 (diff) | |
| download | linux-stable-017c59c042d01fc84cae7a8ea475861e702c77ab.tar.gz linux-stable-017c59c042d01fc84cae7a8ea475861e702c77ab.tar.bz2 linux-stable-017c59c042d01fc84cae7a8ea475861e702c77ab.zip | |
relay: Use per CPU constructs for the relay channel buffer pointers
relay essentially needs to maintain a per CPU array of channel buffer
pointers but it manually creates that array. Instead its better to use
the per CPU constructs, provided by the kernel, to allocate & access the
array of pointer to channel buffers.
Signed-off-by: Akash Goel <akash.goel@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://lkml.kernel.org/r/1470909140-25919-1-git-send-email-akash.goel@intel.com
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'include/linux/relay.h')
| -rw-r--r-- | include/linux/relay.h | 17 |
1 files changed, 10 insertions, 7 deletions
diff --git a/include/linux/relay.h b/include/linux/relay.h index d7c8359693c6..eb295e373b90 100644 --- a/include/linux/relay.h +++ b/include/linux/relay.h @@ -19,6 +19,7 @@ #include <linux/fs.h> #include <linux/poll.h> #include <linux/kref.h> +#include <linux/percpu.h> /* * Tracks changes to rchan/rchan_buf structs @@ -63,7 +64,7 @@ struct rchan struct kref kref; /* channel refcount */ void *private_data; /* for user-defined data */ size_t last_toobig; /* tried to log event > subbuf size */ - struct rchan_buf *buf[NR_CPUS]; /* per-cpu channel buffers */ + struct rchan_buf ** __percpu buf; /* per-cpu channel buffers */ int is_global; /* One global buffer ? */ struct list_head list; /* for channel list */ struct dentry *parent; /* parent dentry passed to open */ @@ -204,7 +205,7 @@ static inline void relay_write(struct rchan *chan, struct rchan_buf *buf; local_irq_save(flags); - buf = chan->buf[smp_processor_id()]; + buf = *this_cpu_ptr(chan->buf); if (unlikely(buf->offset + length > chan->subbuf_size)) length = relay_switch_subbuf(buf, length); memcpy(buf->data + buf->offset, data, length); @@ -230,12 +231,12 @@ static inline void __relay_write(struct rchan *chan, { struct rchan_buf *buf; - buf = chan->buf[get_cpu()]; + buf = *get_cpu_ptr(chan->buf); if (unlikely(buf->offset + length > buf->chan->subbuf_size)) length = relay_switch_subbuf(buf, length); memcpy(buf->data + buf->offset, data, length); buf->offset += length; - put_cpu(); + put_cpu_ptr(chan->buf); } /** @@ -251,17 +252,19 @@ static inline void __relay_write(struct rchan *chan, */ static inline void *relay_reserve(struct rchan *chan, size_t length) { - void *reserved; - struct rchan_buf *buf = chan->buf[smp_processor_id()]; + void *reserved = NULL; + struct rchan_buf *buf = *get_cpu_ptr(chan->buf); if (unlikely(buf->offset + length > buf->chan->subbuf_size)) { length = relay_switch_subbuf(buf, length); if (!length) - return NULL; + goto end; } reserved = buf->data + buf->offset; buf->offset += length; +end: + put_cpu_ptr(chan->buf); return reserved; } |