mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2025-01-10 15:19:51 +00:00
dmaengine: at_xdmac: Replace zero-length array with flexible-array
The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] sizeof(flexible-array-member) triggers a warning because flexible array members have incomplete type[1]. There are some instances of code in which the sizeof operator is being incorrectly/erroneously applied to zero-length arrays and the result is zero. Such instances may be hiding some bugs. So, this work (flexible-array member conversions) will also help to get completely rid of those sorts of issues. This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> Acked-by: Ludovic Desroches<ludovic.desroches@microchip.com> Link: https://lore.kernel.org/r/20200507190046.GA15298@embeddedor Signed-off-by: Vinod Koul <vkoul@kernel.org>
This commit is contained in:
parent
e05a0b78f3
commit
d9fd428a30
@ -212,7 +212,7 @@ struct at_xdmac {
|
||||
struct clk *clk;
|
||||
u32 save_gim;
|
||||
struct dma_pool *at_xdmac_desc_pool;
|
||||
struct at_xdmac_chan chan[0];
|
||||
struct at_xdmac_chan chan[];
|
||||
};
|
||||
|
||||
|
||||
|
Loading…
x
Reference in New Issue
Block a user