From b12fdf7da28ff9709a72814e141646e20d97ed21 Mon Sep 17 00:00:00 2001 From: Zachary Warren Date: Sat, 17 Jan 2015 22:39:53 +1100 Subject: [PATCH] staging: unisys: rework signal remove/insert to avoid sparse lock warnings Avoids the following warnings from sparse: visorchannel_funcs.c:457:9: warning: context imbalance in 'visorchannel_signalremove' - different lock contexts for basic block visorchannel_funcs.c:512:9: warning: context imbalance in 'visorchannel_signalinsert' - different lock contexts for basic These warnings are false positives. Sparse can't track conditional contexts. The change puts the lock/unlock into the same context by splitting the insert/remove functions each into a wrapper function that does locking if necessary and an inner function that does the insert/remove operation. Signed-off-by: Zachary Warren Acked-by: Benjamin Romer Signed-off-by: Greg Kroah-Hartman --- .../unisys/visorchannel/visorchannel_funcs.c | 103 +++++++++--------- 1 file changed, 54 insertions(+), 49 deletions(-) diff --git a/drivers/staging/unisys/visorchannel/visorchannel_funcs.c b/drivers/staging/unisys/visorchannel/visorchannel_funcs.c index 6c48ba13951f..0188ef866fdd 100644 --- a/drivers/staging/unisys/visorchannel/visorchannel_funcs.c +++ b/drivers/staging/unisys/visorchannel/visorchannel_funcs.c @@ -411,27 +411,21 @@ safe_sig_queue_validate(struct signal_queue_header *psafe_sqh, return 1; } /* end safe_sig_queue_validate */ -BOOL -visorchannel_signalremove(struct visorchannel *channel, u32 queue, void *msg) +static BOOL +signalremove_inner(struct visorchannel *channel, u32 queue, void *msg) { - BOOL rc = FALSE; struct signal_queue_header sig_hdr; - if (channel->needs_lock) - spin_lock(&channel->remove_lock); - if (!sig_read_header(channel, queue, &sig_hdr)) { - rc = FALSE; - goto cleanup; - } - if (sig_hdr.head == sig_hdr.tail) { - rc = FALSE; /* no signals to remove */ - goto cleanup; + return FALSE; } + if (sig_hdr.head == sig_hdr.tail) + return FALSE; /* no signals to remove */ + sig_hdr.tail = (sig_hdr.tail + 1) % sig_hdr.max_slots; if (!sig_read_data(channel, queue, &sig_hdr, sig_hdr.tail, msg)) { - ERRDRV("sig_read_data failed: (status=%d)\n", rc); - goto cleanup; + ERRDRV("sig_read_data failed\n"); + return FALSE; } sig_hdr.num_received++; @@ -440,53 +434,54 @@ visorchannel_signalremove(struct visorchannel *channel, u32 queue, void *msg) */ mb(); /* required for channel synch */ if (!SIG_WRITE_FIELD(channel, queue, &sig_hdr, tail)) { - ERRDRV("visor_memregion_write of Tail failed: (status=%d)\n", - rc); - goto cleanup; + ERRDRV("visor_memregion_write of Tail failed\n"); + return FALSE; } if (!SIG_WRITE_FIELD(channel, queue, &sig_hdr, num_received)) { - ERRDRV("visor_memregion_write of NumSignalsReceived failed: (status=%d)\n", - rc); - goto cleanup; + ERRDRV("visor_memregion_write of NumSignalsReceived failed\n"); + return FALSE; } - rc = TRUE; -cleanup: - if (channel->needs_lock) + return TRUE; +} + +BOOL +visorchannel_signalremove(struct visorchannel *channel, u32 queue, void *msg) +{ + BOOL rc; + + if (channel->needs_lock) { + spin_lock(&channel->remove_lock); + rc = signalremove_inner(channel, queue, msg); spin_unlock(&channel->remove_lock); + } else { + rc = signalremove_inner(channel, queue, msg); + } return rc; } EXPORT_SYMBOL_GPL(visorchannel_signalremove); -BOOL -visorchannel_signalinsert(struct visorchannel *channel, u32 queue, void *msg) +static BOOL +signalinsert_inner(struct visorchannel *channel, u32 queue, void *msg) { - BOOL rc = FALSE; struct signal_queue_header sig_hdr; - if (channel->needs_lock) - spin_lock(&channel->insert_lock); - if (!sig_read_header(channel, queue, &sig_hdr)) { - rc = FALSE; - goto cleanup; + return FALSE; } sig_hdr.head = ((sig_hdr.head + 1) % sig_hdr.max_slots); if (sig_hdr.head == sig_hdr.tail) { sig_hdr.num_overflows++; - if (!SIG_WRITE_FIELD(channel, queue, &sig_hdr, num_overflows)) { - ERRDRV("visor_memregion_write of NumOverflows failed: (status=%d)\n", - rc); - goto cleanup; - } - rc = FALSE; - goto cleanup; + if (!SIG_WRITE_FIELD(channel, queue, &sig_hdr, num_overflows)) + ERRDRV("visor_memregion_write of NumOverflows failed\n"); + + return FALSE; } if (!sig_write_data(channel, queue, &sig_hdr, sig_hdr.head, msg)) { - ERRDRV("sig_write_data failed: (status=%d)\n", rc); - goto cleanup; + ERRDRV("sig_write_data failed\n"); + return FALSE; } sig_hdr.num_sent++; @@ -495,19 +490,29 @@ visorchannel_signalinsert(struct visorchannel *channel, u32 queue, void *msg) */ mb(); /* required for channel synch */ if (!SIG_WRITE_FIELD(channel, queue, &sig_hdr, head)) { - ERRDRV("visor_memregion_write of Head failed: (status=%d)\n", - rc); - goto cleanup; + ERRDRV("visor_memregion_write of Head failed\n"); + return FALSE; } if (!SIG_WRITE_FIELD(channel, queue, &sig_hdr, num_sent)) { - ERRDRV("visor_memregion_write of NumSignalsSent failed: (status=%d)\n", - rc); - goto cleanup; + ERRDRV("visor_memregion_write of NumSignalsSent failed\n"); + return FALSE; } - rc = TRUE; -cleanup: - if (channel->needs_lock) + + return TRUE; +} + +BOOL +visorchannel_signalinsert(struct visorchannel *channel, u32 queue, void *msg) +{ + BOOL rc; + + if (channel->needs_lock) { + spin_lock(&channel->insert_lock); + rc = signalinsert_inner(channel, queue, msg); spin_unlock(&channel->insert_lock); + } else { + rc = signalinsert_inner(channel, queue, msg); + } return rc; } -- 2.30.2