From: Boris Brezillon <boris.brezillon@bootlin.com>
To: <Tudor.Ambarus@microchip.com>
Cc: <marek.vasut@gmail.com>, <dwmw2@infradead.org>,
<computersforpeace@gmail.com>, <richard@nod.at>,
<linux-mtd@lists.infradead.org>, <linux-kernel@vger.kernel.org>,
<yogeshnarayan.gaur@nxp.com>, <cyrille.pitchen@wedev4u.fr>
Subject: Re: [PATCH 3/7] mtd: spi-nor: add restriction for nmaps in smpt parser
Date: Thu, 8 Nov 2018 14:08:26 +0100 [thread overview]
Message-ID: <20181108140826.428b77ed@bbrezillon> (raw)
In-Reply-To: <20181108135447.36a0314c@bbrezillon>
On Thu, 8 Nov 2018 13:54:47 +0100
Boris Brezillon <boris.brezillon@bootlin.com> wrote:
> > - while (i < smpt_len) {
> > + for (nmaps = 0; i < smpt_len; nmaps++) {
> > + /*
> > + * The map selector is limited to a maximum of 8 bits, allowing
> > + * for a maximum of 256 possible map configurations. The total
> > + * number of map configurations should be addressable by the
> > + * total number of bits described by the detection commands.
> > + */
> > + if (ncmds && nmaps >= (1 << (ncmds + 1)))
> > + break;
> > +
>
> Maybe I missed something but it sounds like this change is just
> optimizing the SPMT parsing a bit, and to be honest, I'm not sure this
> is really needed. Most of the time, smpt_len will be rather small, so
> trying to bail out earlier is not bringing much perf improvements.
To make it clearer, I don't think the extra complexity is worth the tiny
perf improvement.
next prev parent reply other threads:[~2018-11-08 13:08 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-08 11:07 [PATCH 0/7] mtd: spi-nor: fixes found when debugging smpt Tudor.Ambarus
2018-11-08 11:07 ` [PATCH 1/7] mtd: spi-nor: don't drop sfdp data if optional parsers fail Tudor.Ambarus
2018-11-08 11:07 ` [PATCH 2/7] mtd: spi-nor: fix iteration over smpt array Tudor.Ambarus
2018-11-08 12:50 ` Boris Brezillon
2018-11-08 11:07 ` [PATCH 3/7] mtd: spi-nor: add restriction for nmaps in smpt parser Tudor.Ambarus
2018-11-08 12:54 ` Boris Brezillon
2018-11-08 13:08 ` Boris Brezillon [this message]
2018-11-08 13:58 ` Tudor.Ambarus
2018-11-08 14:15 ` Boris Brezillon
2018-11-08 14:48 ` Tudor.Ambarus
2018-11-08 14:54 ` Boris Brezillon
2018-11-08 15:00 ` Tudor.Ambarus
2018-11-08 11:07 ` [PATCH 4/7] mtd: spi-nor: don't overwrite errno in spi_nor_get_map_in_use() Tudor.Ambarus
2018-11-08 11:07 ` [PATCH 5/7] mtd: spi_nor: pass DMA-able buffer to spi_nor_read_raw() Tudor.Ambarus
2018-11-08 13:01 ` Boris Brezillon
2018-11-08 11:07 ` [PATCH 6/7] mtd: spi-nor: ensure memory used for nor->read() is DMA safe Tudor.Ambarus
2018-11-08 13:03 ` Boris Brezillon
2018-11-08 11:07 ` [PATCH 7/7] mtd: spi-nor: remove unneeded smpt zeroization Tudor.Ambarus
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