From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: base64 Subject: dmaengine: dmatest: Remove use of VLAs From: Sinan Kaya Message-Id: Date: Mon, 09 Apr 2018 19:19:16 -0400 To: Laura Abbott Cc: Vinod Koul , Dan Williams , dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com, Kees Cook , dmaengine-owner@vger.kernel.org List-ID: T24gMjAxOC0wNC0wOSAxOToxNCwgTGF1cmEgQWJib3R0IHdyb3RlOgo+IE9uIDA0LzA5LzIwMTgg MDM6NDggUE0sIFNpbmFuIEtheWEgd3JvdGU6Cj4+IE9uIDQvOS8yMDE4IDU6MDYgUE0sIExhdXJh IEFiYm90dCB3cm90ZToKPj4+ICsJCQkvKiBkc3RfY250IGNhbid0IGJlIG1vcmUgdGhhbiB1OCAq Lwo+Pj4gKwkJCWRtYV9hZGRyX3QgZG1hX3BxWzI1NV07Cj4+IAo+PiBUaGlzIGlzIDJrIHN0YWNr IHNwYWNlIG9uIDY0IGJpdCBhcmNoaXRlY3R1cmVzLiBJc24ndCB0aGF0IGEgbG90Pwo+PiAKPiAK PiBEZXBlbmRzIG9uIHlvdXIgZGVmaW5pdGlvbiBvZiAnYSBsb3QnLiBNeSBhc3N1bXB0aW9uIHdh cyB0aGF0Cj4gc2luY2UgdGhpcyB3YXMgYSB0ZXN0IG1vZHVsZSB0aGVyZSB3b3VsZCBiZSBzb21l IHdpbGxpbmduZXNzCj4gdG8gYmUgYSBiaXQgbW9yZSBnZW5lcm91cy4gVGhlIHByb2JsZW0gaXMg dGhlIGFycmF5IHNpemUgaXMKPiBiYXNlZCBvZmYgb2YgdGhlIHBhcmFtZXRlcnMgcGFzc2VkIGlu LCBhbHRob3VnaCBvZGRseSBlbm91Z2gKPiBpdCdzIGJhc2VkIG9mZiBvZiB0aGUgbWluaW11bSBv ZiB0d28gdmFyaWFibGVzLiBJZiB5b3UgaGF2ZQo+IGEgc3VnZ2VzdGlvbiBmb3IgYSB0aWdodGVy IGJvdW5kIHdlIGNhbiB1c2UgdGhhdC4gQW5vdGhlcgo+IG9wdGlvbiBpcyB0byBqdXN0IHN3aXRj aCB0byBhbGxvY2F0aW5nIHRoZSBhcnJheSB3aXRoIGttYWxsb2MuCj4gVGhhdCBtaWdodCBiZSBy ZWFzb25hYmxlIGhlcmUgc2luY2UgdGhlcmUncyBvdGhlciBzZXR1cAo+IHRoYXQgaGFwcGVucyBi ZWZvcmUgdGhlIHRlc3Qgc3RhcnRzLgoKSSB0aGluayBhbGxvY2F0aW9uIGlzIGEgYmV0dGVyIGNo b2ljZS4KCj4gCj4gVGhhbmtzLAo+IExhdXJhCj4gCj4gLS0KPiBUbyB1bnN1YnNjcmliZSBmcm9t IHRoaXMgbGlzdDogc2VuZCB0aGUgbGluZSAidW5zdWJzY3JpYmUgZG1hZW5naW5lIiBpbgo+IHRo ZSBib2R5IG9mIGEgbWVzc2FnZSB0byBtYWpvcmRvbW9Admdlci5rZXJuZWwub3JnCj4gTW9yZSBt YWpvcmRvbW8gaW5mbyBhdCAgaHR0cDovL3ZnZXIua2VybmVsLm9yZy9tYWpvcmRvbW8taW5mby5o dG1sCi0tLQpUbyB1bnN1YnNjcmliZSBmcm9tIHRoaXMgbGlzdDogc2VuZCB0aGUgbGluZSAidW5z dWJzY3JpYmUgZG1hZW5naW5lIiBpbgp0aGUgYm9keSBvZiBhIG1lc3NhZ2UgdG8gbWFqb3Jkb21v QHZnZXIua2VybmVsLm9yZwpNb3JlIG1ham9yZG9tbyBpbmZvIGF0ICBodHRwOi8vdmdlci5rZXJu ZWwub3JnL21ham9yZG9tby1pbmZvLmh0bWwK From mboxrd@z Thu Jan 1 00:00:00 1970 MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Mon, 09 Apr 2018 19:19:16 -0400 From: okaya@codeaurora.org Subject: Re: [PATCH] dmaengine: dmatest: Remove use of VLAs In-Reply-To: <9bdd8bb4-b6d9-e170-b585-b2dc3b8f0d67@redhat.com> References: <20180409210603.3575-1-labbott@redhat.com> <4491bde2-cf38-5103-0634-1986ecd32a7c@codeaurora.org> <9bdd8bb4-b6d9-e170-b585-b2dc3b8f0d67@redhat.com> Message-ID: To: Laura Abbott Cc: Vinod Koul , Dan Williams , dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com, Kees Cook , dmaengine-owner@vger.kernel.org List-ID: On 2018-04-09 19:14, Laura Abbott wrote: > On 04/09/2018 03:48 PM, Sinan Kaya wrote: >> On 4/9/2018 5:06 PM, Laura Abbott wrote: >>> + /* dst_cnt can't be more than u8 */ >>> + dma_addr_t dma_pq[255]; >> >> This is 2k stack space on 64 bit architectures. Isn't that a lot? >> > > Depends on your definition of 'a lot'. My assumption was that > since this was a test module there would be some willingness > to be a bit more generous. The problem is the array size is > based off of the parameters passed in, although oddly enough > it's based off of the minimum of two variables. If you have > a suggestion for a tighter bound we can use that. Another > option is to just switch to allocating the array with kmalloc. > That might be reasonable here since there's other setup > that happens before the test starts. I think allocation is a better choice. > > Thanks, > Laura > > -- > To unsubscribe from this list: send the line "unsubscribe dmaengine" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html