On Tue, May 28, 2019 at 08:32:57AM +0800, Gen Zhang wrote: > devm_kmalloc() is used to allocate memory for a driver dev. Comments > above the definition and doc > (https://www.kernel.org/doc/Documentation/driver-model/devres.txt) all > imply that allocated the memory is automatically freed on driver attach, > no matter allocation fail or not. However, I examined the code, and > there are many sites that devm_kfree() is used to free devm_kmalloc(). > e.g. hisi_sas_debugfs_init() in drivers/scsi/hisi_sas/hisi_sas_main.c. > So I am totally confused about this issue. Can anybody give me some > guidance? When should we use devm_kfree()?
If you "know" you need to free the memory now, call devm_kfree(). If you want to wait for it to be cleaned up latter, like normal, then do not call it. Do you have a driver that you think uses it incorrectly? thanks, greg k-h
