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From: ezequiel.garcia@free-electrons.com (Ezequiel Garcia)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v3 12/28] mtd: nand: pxa3xx: Use a completion to signal device ready
Date: Tue, 5 Nov 2013 21:46:42 -0300	[thread overview]
Message-ID: <20131106004641.GG11759@localhost> (raw)
In-Reply-To: <20131106002759.GF11759@localhost>

On Tue, Nov 05, 2013 at 09:27:59PM -0300, Ezequiel Garcia wrote:
> > 
> > I believe your handling of this 'is_ready' bit is a little unwise, as
> > you are actually creating extra concurrency that is unneeded. I'll
> > summarize what you're doing with this 'is_ready' field:
> > 
> >   cmdfunc() -> sets info->is_ready=0 for appropriate commands
> >             -> kicks off the hardware
> > 
> > The following two sequences may then occur concurrently:
> > 
> >   (1) pxa3xx_nand_irq -> ready interrupt occurs
> >                       -> set info->is_ready=1
> > 		      -> signal 'dev_ready' completion
> > 
> >   (2) waitfunc -> check info->is_ready, if it is 0...
> >                   |_ ... wait for the dev_ready completion
> > 
> > Instead of setting info->is_ready=1 under (1), you could set it in (2),

So, after some more careful thought and some testings, it seems you're
correct. Setting is_read in waitfunc() results in a non-racy solution and
the atomic_t can go away.

I'll take a look at the other remaining issues and see about preparing
a v4, so we can try to converge quick enough for v3.14.

Thanks!
-- 
Ezequiel Garc?a, Free Electrons
Embedded Linux, Kernel and Android Engineering
http://free-electrons.com

  reply	other threads:[~2013-11-06  0:46 UTC|newest]

Thread overview: 57+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-11-05 12:55 [PATCH v3 00/28] Armada 370/XP NAND support Ezequiel Garcia
2013-11-05 12:55 ` [PATCH v3 01/28] clk: mvebu: Add Core Divider clock Ezequiel Garcia
2013-11-05 12:55 ` [PATCH v3 02/28] ARM: mvebu: Add Core Divider clock device-tree binding Ezequiel Garcia
2013-11-05 12:55 ` [PATCH v3 03/28] ARM: mvebu: Add a 2 GHz fixed-clock Armada 370/XP Ezequiel Garcia
2013-11-05 12:55 ` [PATCH v3 04/28] ARM: mvebu: Add the core-divider clock to " Ezequiel Garcia
2013-11-05 12:55 ` [PATCH v3 05/28] mtd: nand: pxa3xx: Make config menu show supported platforms Ezequiel Garcia
2013-11-05 12:55 ` [PATCH v3 06/28] mtd: nand: pxa3xx: Prevent sub-page writes Ezequiel Garcia
2013-11-05 12:55 ` [PATCH v3 07/28] mtd: nand: pxa3xx: Early variant detection Ezequiel Garcia
2013-11-05 12:55 ` [PATCH v3 08/28] mtd: nand: pxa3xx: Use chip->cmdfunc instead of the internal Ezequiel Garcia
2013-11-05 12:55 ` [PATCH v3 09/28] mtd: nand: pxa3xx: Split FIFO size from to-be-read FIFO count Ezequiel Garcia
2013-11-05 12:55 ` [PATCH v3 10/28] mtd: nand: pxa3xx: Replace host->page_size by mtd->writesize Ezequiel Garcia
2013-11-05 12:55 ` [PATCH v3 11/28] mtd: nand: pxa3xx: Add a nice comment to pxa3xx_set_datasize() Ezequiel Garcia
2013-11-05 12:55 ` [PATCH v3 12/28] mtd: nand: pxa3xx: Use a completion to signal device ready Ezequiel Garcia
2013-11-05 19:51   ` Brian Norris
2013-11-06  0:28     ` Ezequiel Garcia
2013-11-06  0:46       ` Ezequiel Garcia [this message]
2013-11-05 12:55 ` [PATCH v3 13/28] mtd: nand: pxa3xx: Add bad block handling Ezequiel Garcia
2013-11-05 18:23   ` Brian Norris
2013-11-05 23:40     ` Ezequiel Garcia
2013-11-06  1:36       ` Brian Norris
2013-11-05 12:55 ` [PATCH v3 14/28] mtd: nand: pxa3xx: Add driver-specific ECC BCH support Ezequiel Garcia
2013-11-05 18:31   ` Brian Norris
2013-11-05 23:24     ` Ezequiel Garcia
2013-11-05 12:55 ` [PATCH v3 15/28] mtd: nand: pxa3xx: Clear cmd buffer #3 (NDCB3) on command start Ezequiel Garcia
2013-11-05 12:55 ` [PATCH v3 16/28] mtd: nand: pxa3xx: Add helper function to set page address Ezequiel Garcia
2013-11-05 12:55 ` [PATCH v3 17/28] mtd: nand: pxa3xx: Remove READ0 switch/case falltrough Ezequiel Garcia
2013-11-05 12:55 ` [PATCH v3 18/28] mtd: nand: pxa3xx: Split prepare_command_pool() in two stages Ezequiel Garcia
2013-11-05 18:32   ` Brian Norris
2013-11-05 12:55 ` [PATCH v3 19/28] mtd: nand: pxa3xx: Move the data buffer clean to prepare_start_command() Ezequiel Garcia
2013-11-05 12:55 ` [PATCH v3 20/28] mtd: nand: pxa3xx: Fix SEQIN column address set Ezequiel Garcia
2013-11-05 12:55 ` [PATCH v3 21/28] mtd: nand: pxa3xx: Add a read/write buffers markers Ezequiel Garcia
2013-11-05 12:55 ` [PATCH v3 22/28] mtd: nand: pxa3xx: Introduce multiple page I/O support Ezequiel Garcia
2013-11-05 19:04   ` Brian Norris
2013-11-06  1:13     ` Ezequiel Garcia
2013-11-06  2:20       ` Brian Norris
2013-11-06  2:27         ` Brian Norris
2013-11-06  3:35         ` Ezequiel Garcia
2013-11-06 11:32         ` Ezequiel Garcia
2013-11-18 18:10           ` Brian Norris
2013-11-18 18:33             ` Ezequiel Garcia
2013-11-18 18:50               ` Brian Norris
2013-12-04 21:41                 ` Brian Norris
2013-11-05 19:08   ` Brian Norris
2013-11-05 12:55 ` [PATCH v3 23/28] mtd: nand: pxa3xx: Add multiple chunk write support Ezequiel Garcia
2013-11-05 12:55 ` [PATCH v3 24/28] mtd: nand: pxa3xx: Add ECC BCH correctable errors detection Ezequiel Garcia
2013-11-05 12:55 ` [PATCH v3 25/28] ARM: mvebu: Add support for NAND controller in Armada 370/XP Ezequiel Garcia
2013-11-05 13:29   ` Jason Cooper
2013-11-05 13:51     ` Ezequiel Garcia
2013-11-05 15:15       ` Jason Cooper
2013-11-05 15:37         ` Ezequiel Garcia
2013-11-06  8:24         ` Thomas Petazzoni
2013-11-06 11:42           ` Jason Cooper
2013-11-06 12:56             ` Thomas Petazzoni
2013-11-06 17:21               ` Jason Cooper
2013-11-05 12:55 ` [PATCH v3 26/28] ARM: mvebu: Enable NAND controller in Armada XP GP board Ezequiel Garcia
2013-11-05 12:55 ` [PATCH v3 27/28] ARM: mvebu: Enable NAND controller in Armada 370 Mirabox Ezequiel Garcia
2013-11-05 12:55 ` [PATCH v3 28/28] mtd: nand: pxa3xx: Add documentation about the controller Ezequiel Garcia

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