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author | Linus Torvalds <torvalds@linux-foundation.org> | 2013-05-25 05:12:15 +0400 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-05-25 05:12:15 +0400 |
commit | 9cf1848278a41f8d5f69b26bca546cfd2d5677d8 (patch) | |
tree | 2628cd3e8e3ca1acfe81e636b082c285d97640d9 /drivers/char/random.c | |
parent | 00cec111ac477ba71c99043358f17e9bb4d335fe (diff) | |
parent | 03e04f048d2774aabd126fbad84729d4ba9dc40a (diff) | |
download | linux-9cf1848278a41f8d5f69b26bca546cfd2d5677d8.tar.xz |
Merge branch 'akpm' (incoming from Andrew Morton)
Merge fixes from Andrew Morton:
"A bunch of fixes and one simple fbdev driver which missed the merge
window because people will still talking about it (to no great
effect)."
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (30 commits)
aio: fix kioctx not being freed after cancellation at exit time
mm/pagewalk.c: walk_page_range should avoid VM_PFNMAP areas
drivers/rtc/rtc-max8998.c: check for pdata presence before dereferencing
ocfs2: goto out_unlock if ocfs2_get_clusters_nocache() failed in ocfs2_fiemap()
random: fix accounting race condition with lockless irq entropy_count update
drivers/char/random.c: fix priming of last_data
mm/memory_hotplug.c: fix printk format warnings
nilfs2: fix issue of nilfs_set_page_dirty() for page at EOF boundary
drivers/block/brd.c: fix brd_lookup_page() race
fbdev: FB_GOLDFISH should depend on HAS_DMA
drivers/rtc/rtc-pl031.c: pass correct pointer to free_irq()
auditfilter.c: fix kernel-doc warnings
aio: fix io_getevents documentation
revert "selftest: add simple test for soft-dirty bit"
drivers/leds/leds-ot200.c: fix error caused by shifted mask
mm/THP: use pmd_populate() to update the pmd with pgtable_t pointer
linux/kernel.h: fix kernel-doc warning
mm compaction: fix of improper cache flush in migration code
rapidio/tsi721: fix bug in MSI interrupt handling
hfs: avoid crash in hfs_bnode_create
...
Diffstat (limited to 'drivers/char/random.c')
-rw-r--r-- | drivers/char/random.c | 54 |
1 files changed, 31 insertions, 23 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c index cd9a6211dcad..35487e8ded59 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -865,16 +865,24 @@ static size_t account(struct entropy_store *r, size_t nbytes, int min, if (r->entropy_count / 8 < min + reserved) { nbytes = 0; } else { + int entropy_count, orig; +retry: + entropy_count = orig = ACCESS_ONCE(r->entropy_count); /* If limited, never pull more than available */ - if (r->limit && nbytes + reserved >= r->entropy_count / 8) - nbytes = r->entropy_count/8 - reserved; - - if (r->entropy_count / 8 >= nbytes + reserved) - r->entropy_count -= nbytes*8; - else - r->entropy_count = reserved; + if (r->limit && nbytes + reserved >= entropy_count / 8) + nbytes = entropy_count/8 - reserved; + + if (entropy_count / 8 >= nbytes + reserved) { + entropy_count -= nbytes*8; + if (cmpxchg(&r->entropy_count, orig, entropy_count) != orig) + goto retry; + } else { + entropy_count = reserved; + if (cmpxchg(&r->entropy_count, orig, entropy_count) != orig) + goto retry; + } - if (r->entropy_count < random_write_wakeup_thresh) + if (entropy_count < random_write_wakeup_thresh) wakeup_write = 1; } @@ -957,10 +965,23 @@ static ssize_t extract_entropy(struct entropy_store *r, void *buf, { ssize_t ret = 0, i; __u8 tmp[EXTRACT_SIZE]; + unsigned long flags; /* if last_data isn't primed, we need EXTRACT_SIZE extra bytes */ - if (fips_enabled && !r->last_data_init) - nbytes += EXTRACT_SIZE; + if (fips_enabled) { + spin_lock_irqsave(&r->lock, flags); + if (!r->last_data_init) { + r->last_data_init = true; + spin_unlock_irqrestore(&r->lock, flags); + trace_extract_entropy(r->name, EXTRACT_SIZE, + r->entropy_count, _RET_IP_); + xfer_secondary_pool(r, EXTRACT_SIZE); + extract_buf(r, tmp); + spin_lock_irqsave(&r->lock, flags); + memcpy(r->last_data, tmp, EXTRACT_SIZE); + } + spin_unlock_irqrestore(&r->lock, flags); + } trace_extract_entropy(r->name, nbytes, r->entropy_count, _RET_IP_); xfer_secondary_pool(r, nbytes); @@ -970,19 +991,6 @@ static ssize_t extract_entropy(struct entropy_store *r, void *buf, extract_buf(r, tmp); if (fips_enabled) { - unsigned long flags; - - - /* prime last_data value if need be, per fips 140-2 */ - if (!r->last_data_init) { - spin_lock_irqsave(&r->lock, flags); - memcpy(r->last_data, tmp, EXTRACT_SIZE); - r->last_data_init = true; - nbytes -= EXTRACT_SIZE; - spin_unlock_irqrestore(&r->lock, flags); - extract_buf(r, tmp); - } - spin_lock_irqsave(&r->lock, flags); if (!memcmp(tmp, r->last_data, EXTRACT_SIZE)) panic("Hardware RNG duplicated output!\n"); |