From: Paolo Bonzini <pbonzini@redhat.com> To: James Bottomley <James.Bottomley@HansenPartnership.com> Cc: Wanlong Gao <gaowanlong@cn.fujitsu.com>, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-scsi@vger.kernel.org, virtualization@lists.linux-foundation.org, rusty@rustcorp.com.au, mst@redhat.com, asias@redhat.com Subject: Re: [PATCH V5 1/5] virtio-scsi: redo allocation of target data Date: Tue, 19 Mar 2013 12:45:06 +0100 [thread overview] Message-ID: <51484FC2.6030601@redhat.com> (raw) In-Reply-To: <1363692727.2377.53.camel@dabdike.int.hansenpartnership.com> Il 19/03/2013 12:32, James Bottomley ha scritto: > On Tue, 2013-03-19 at 17:57 +0800, Wanlong Gao wrote: >> From: Paolo Bonzini <pbonzini@redhat.com> >> >> virtio_scsi_target_state is now empty. We will find new uses for it in >> the next few patches, so this patch does not drop it completely. >> However, having dropped the sglist flexible array member, we can turn >> the tgt array-of-pointers into a simple array. This simplifies the >> allocation. >> >> Even simpler would be to place the virtio_scsi_target_state structs in a >> flexible array member at the end of struct virtio_scsi. But we do not >> do that, because we will place the virtqueues there in the next patches. > > I'm really sorry, but I must have been asleep at the wheel when I let > code like this go in. No modern driver should have fixed arrays for > target information. The way this is supposed to work is that you have > entries in the host template for target_alloc and target_destroy. You > hook into these and attach your struct virtio_scsi_target_state to > scsi_target->hostdata, So that would be sc->device->sdev_target->hostdata. > which you kmalloc in the target_alloc routine and > kfree in the target_destroy routine. Now you get at it from the sdev > with scsi_target(sdev)->hostdata. No messing around with fixed size > arrays and bulk memory allocation and no need to pass in the maximum > target size as a parameter because everything should now happen > dynamically. The maximum target size is not a module parameter, it is given by the host; so the module itself is not placing arbitrary limitation. Still it is a good idea to do it like this. Thanks for the review. Paolo > Since you're redoing the code anyway, can you fix it to work this way? > > Thanks, > > James > >
WARNING: multiple messages have this Message-ID (diff)
From: Paolo Bonzini <pbonzini@redhat.com> To: James Bottomley <James.Bottomley@HansenPartnership.com> Cc: kvm@vger.kernel.org, linux-scsi@vger.kernel.org, mst@redhat.com, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org Subject: Re: [PATCH V5 1/5] virtio-scsi: redo allocation of target data Date: Tue, 19 Mar 2013 12:45:06 +0100 [thread overview] Message-ID: <51484FC2.6030601@redhat.com> (raw) In-Reply-To: <1363692727.2377.53.camel@dabdike.int.hansenpartnership.com> Il 19/03/2013 12:32, James Bottomley ha scritto: > On Tue, 2013-03-19 at 17:57 +0800, Wanlong Gao wrote: >> From: Paolo Bonzini <pbonzini@redhat.com> >> >> virtio_scsi_target_state is now empty. We will find new uses for it in >> the next few patches, so this patch does not drop it completely. >> However, having dropped the sglist flexible array member, we can turn >> the tgt array-of-pointers into a simple array. This simplifies the >> allocation. >> >> Even simpler would be to place the virtio_scsi_target_state structs in a >> flexible array member at the end of struct virtio_scsi. But we do not >> do that, because we will place the virtqueues there in the next patches. > > I'm really sorry, but I must have been asleep at the wheel when I let > code like this go in. No modern driver should have fixed arrays for > target information. The way this is supposed to work is that you have > entries in the host template for target_alloc and target_destroy. You > hook into these and attach your struct virtio_scsi_target_state to > scsi_target->hostdata, So that would be sc->device->sdev_target->hostdata. > which you kmalloc in the target_alloc routine and > kfree in the target_destroy routine. Now you get at it from the sdev > with scsi_target(sdev)->hostdata. No messing around with fixed size > arrays and bulk memory allocation and no need to pass in the maximum > target size as a parameter because everything should now happen > dynamically. The maximum target size is not a module parameter, it is given by the host; so the module itself is not placing arbitrary limitation. Still it is a good idea to do it like this. Thanks for the review. Paolo > Since you're redoing the code anyway, can you fix it to work this way? > > Thanks, > > James > >
next prev parent reply other threads:[~2013-03-19 11:45 UTC|newest] Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top 2013-03-19 9:57 [PATCH V5 0/5] virtio-scsi multiqueue Wanlong Gao 2013-03-19 9:57 ` Wanlong Gao 2013-03-19 9:57 ` [PATCH V5 1/5] virtio-scsi: redo allocation of target data Wanlong Gao 2013-03-19 9:57 ` Wanlong Gao 2013-03-19 11:32 ` James Bottomley 2013-03-19 11:45 ` Paolo Bonzini [this message] 2013-03-19 11:45 ` Paolo Bonzini 2013-03-19 12:00 ` James Bottomley 2013-03-19 9:57 ` [PATCH V5 2/5] virtio-scsi: pass struct virtio_scsi to virtqueue completion function Wanlong Gao 2013-03-19 9:57 ` Wanlong Gao 2013-03-19 9:57 ` [PATCH V5 3/5] virtio-scsi: push vq lock/unlock into virtscsi_vq_done Wanlong Gao 2013-03-19 9:57 ` Wanlong Gao 2013-03-19 9:57 ` [PATCH V5 4/5] virtio-scsi: introduce multiqueue support Wanlong Gao 2013-03-19 9:57 ` Wanlong Gao 2013-03-20 1:46 ` Venkatesh Srinivas 2013-03-20 1:46 ` Venkatesh Srinivas 2013-03-20 7:24 ` Wanlong Gao 2013-03-20 7:24 ` Wanlong Gao 2013-03-20 9:53 ` Paolo Bonzini 2013-03-20 9:53 ` Paolo Bonzini 2013-03-19 9:57 ` [PATCH V5 5/5] virtio-scsi: reset virtqueue affinity when doing cpu hotplug Wanlong Gao 2013-03-19 9:57 ` Wanlong Gao
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