Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756067Ab0LMUy1 (ORCPT ); Mon, 13 Dec 2010 15:54:27 -0500 Received: from swampdragon.chaosbits.net ([90.184.90.115]:20468 "EHLO swampdragon.chaosbits.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755927Ab0LMUyZ (ORCPT ); Mon, 13 Dec 2010 15:54:25 -0500 Date: Mon, 13 Dec 2010 21:48:02 +0100 (CET) From: Jesper Juhl To: Hank Janssen cc: gregkh@suse.de, linux-kernel@vger.kernel.org, devel@linuxdriverproject.org, virtualization@lists.osdl.org, Haiyang Zhang , Evgeniy Polyakov , Ky Srinivasan Subject: Re: [PATCH 1/1] hv: Use only one receive buffer per channel and kmalloc on initialize In-Reply-To: <1292272498-29483-1-git-send-email-hjanssen@microsoft.com> Message-ID: References: <1292272498-29483-1-git-send-email-hjanssen@microsoft.com> User-Agent: Alpine 2.00 (LNX 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8278 Lines: 252 On Mon, 13 Dec 2010, Hank Janssen wrote: > Correct issue with not checking kmalloc return value. > This fix now only uses one receive buffer for all hv_utils > channels, and will do only one kmalloc on init and will return > with a -ENOMEM if kmalloc fails on initialize. > > Thanks to Evgeniy Polyakov for pointing this out. > And thanks to Jesper Juhl and Ky Srinivasan > for suggesting a better implementation of > my original patch. > > Signed-off-by: Haiyang Zhang > Signed-off-by: Hank Janssen > Cc: Evgeniy Polyakov > Cc: Jesper Juhl > Cc: Ky Srinivasan > > --- > drivers/staging/hv/hv_utils.c | 84 +++++++++++++++++++++------------------- > 1 files changed, 44 insertions(+), 40 deletions(-) > > diff --git a/drivers/staging/hv/hv_utils.c b/drivers/staging/hv/hv_utils.c > index 53e1e29..e0ecc23 100644 > --- a/drivers/staging/hv/hv_utils.c > +++ b/drivers/staging/hv/hv_utils.c > @@ -38,12 +38,14 @@ > #include "vmbus_api.h" > #include "utils.h" > > +static u8 *shut_txf_buf; > +static u8 *time_txf_buf; > +static u8 *hbeat_txf_buf; > > static void shutdown_onchannelcallback(void *context) > { > struct vmbus_channel *channel = context; > - u8 *buf; > - u32 buflen, recvlen; > + u32 recvlen; > u64 requestid; > u8 execute_shutdown = false; > > @@ -52,24 +54,23 @@ static void shutdown_onchannelcallback(void *context) > struct icmsg_hdr *icmsghdrp; > struct icmsg_negotiate *negop = NULL; > > - buflen = PAGE_SIZE; > - buf = kmalloc(buflen, GFP_ATOMIC); > - > - vmbus_recvpacket(channel, buf, buflen, &recvlen, &requestid); > + vmbus_recvpacket(channel, shut_txf_buf, > + PAGE_SIZE, &recvlen, &requestid); > > if (recvlen > 0) { > DPRINT_DBG(VMBUS, "shutdown packet: len=%d, requestid=%lld", > recvlen, requestid); > > - icmsghdrp = (struct icmsg_hdr *)&buf[ > + icmsghdrp = (struct icmsg_hdr *)&shut_txf_buf[ > sizeof(struct vmbuspipe_hdr)]; > > if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) { > - prep_negotiate_resp(icmsghdrp, negop, buf); > + prep_negotiate_resp(icmsghdrp, negop, shut_txf_buf); > } else { > - shutdown_msg = (struct shutdown_msg_data *)&buf[ > - sizeof(struct vmbuspipe_hdr) + > - sizeof(struct icmsg_hdr)]; > + shutdown_msg = > + (struct shutdown_msg_data *)&shut_txf_buf[ > + sizeof(struct vmbuspipe_hdr) + > + sizeof(struct icmsg_hdr)]; > > switch (shutdown_msg->flags) { > case 0: > @@ -93,13 +94,11 @@ static void shutdown_onchannelcallback(void *context) > icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION > | ICMSGHDRFLAG_RESPONSE; > > - vmbus_sendpacket(channel, buf, > + vmbus_sendpacket(channel, shut_txf_buf, > recvlen, requestid, > VmbusPacketTypeDataInBand, 0); > } > > - kfree(buf); > - > if (execute_shutdown == true) > orderly_poweroff(false); > } > @@ -150,28 +149,25 @@ static inline void adj_guesttime(u64 hosttime, u8 flags) > static void timesync_onchannelcallback(void *context) > { > struct vmbus_channel *channel = context; > - u8 *buf; > - u32 buflen, recvlen; > + u32 recvlen; > u64 requestid; > struct icmsg_hdr *icmsghdrp; > struct ictimesync_data *timedatap; > > - buflen = PAGE_SIZE; > - buf = kmalloc(buflen, GFP_ATOMIC); > - > - vmbus_recvpacket(channel, buf, buflen, &recvlen, &requestid); > + vmbus_recvpacket(channel, time_txf_buf, > + PAGE_SIZE, &recvlen, &requestid); > > if (recvlen > 0) { > DPRINT_DBG(VMBUS, "timesync packet: recvlen=%d, requestid=%lld", > recvlen, requestid); > > - icmsghdrp = (struct icmsg_hdr *)&buf[ > + icmsghdrp = (struct icmsg_hdr *)&time_txf_buf[ > sizeof(struct vmbuspipe_hdr)]; > > if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) { > - prep_negotiate_resp(icmsghdrp, NULL, buf); > + prep_negotiate_resp(icmsghdrp, NULL, time_txf_buf); > } else { > - timedatap = (struct ictimesync_data *)&buf[ > + timedatap = (struct ictimesync_data *)&time_txf_buf[ > sizeof(struct vmbuspipe_hdr) + > sizeof(struct icmsg_hdr)]; > adj_guesttime(timedatap->parenttime, timedatap->flags); > @@ -180,12 +176,10 @@ static void timesync_onchannelcallback(void *context) > icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION > | ICMSGHDRFLAG_RESPONSE; > > - vmbus_sendpacket(channel, buf, > + vmbus_sendpacket(channel, time_txf_buf, > recvlen, requestid, > VmbusPacketTypeDataInBand, 0); > } > - > - kfree(buf); > } > > /* > @@ -196,30 +190,28 @@ static void timesync_onchannelcallback(void *context) > static void heartbeat_onchannelcallback(void *context) > { > struct vmbus_channel *channel = context; > - u8 *buf; > - u32 buflen, recvlen; > + u32 recvlen; > u64 requestid; > struct icmsg_hdr *icmsghdrp; > struct heartbeat_msg_data *heartbeat_msg; > > - buflen = PAGE_SIZE; > - buf = kmalloc(buflen, GFP_ATOMIC); > - > - vmbus_recvpacket(channel, buf, buflen, &recvlen, &requestid); > + vmbus_recvpacket(channel, hbeat_txf_buf, > + PAGE_SIZE, &recvlen, &requestid); > > if (recvlen > 0) { > DPRINT_DBG(VMBUS, "heartbeat packet: len=%d, requestid=%lld", > recvlen, requestid); > > - icmsghdrp = (struct icmsg_hdr *)&buf[ > + icmsghdrp = (struct icmsg_hdr *)&hbeat_txf_buf[ > sizeof(struct vmbuspipe_hdr)]; > > if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) { > - prep_negotiate_resp(icmsghdrp, NULL, buf); > + prep_negotiate_resp(icmsghdrp, NULL, hbeat_txf_buf); > } else { > - heartbeat_msg = (struct heartbeat_msg_data *)&buf[ > - sizeof(struct vmbuspipe_hdr) + > - sizeof(struct icmsg_hdr)]; > + heartbeat_msg = > + (struct heartbeat_msg_data *)&hbeat_txf_buf[ > + sizeof(struct vmbuspipe_hdr) + > + sizeof(struct icmsg_hdr)]; > > DPRINT_DBG(VMBUS, "heartbeat seq = %lld", > heartbeat_msg->seq_num); > @@ -230,12 +222,10 @@ static void heartbeat_onchannelcallback(void *context) > icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION > | ICMSGHDRFLAG_RESPONSE; > > - vmbus_sendpacket(channel, buf, > + vmbus_sendpacket(channel, hbeat_txf_buf, > recvlen, requestid, > VmbusPacketTypeDataInBand, 0); > } > - > - kfree(buf); > } > > static const struct pci_device_id __initconst > @@ -268,6 +258,16 @@ static int __init init_hyperv_utils(void) > if (!dmi_check_system(hv_utils_dmi_table)) > return -ENODEV; > > + shut_txf_buf = kmalloc(PAGE_SIZE, GFP_ATOMIC); > + time_txf_buf = kmalloc(PAGE_SIZE, GFP_ATOMIC); > + hbeat_txf_buf = kmalloc(PAGE_SIZE, GFP_ATOMIC); > + > + if (!shut_txf_buf || !time_txf_buf || !hbeat_txf_buf) { > + printk(KERN_INFO > + "Unable to allocate memory for receive buffer\n"); > + return -ENOMEM; You are leaking memory in the failure path. If for example one or two allocations succeed but one or two fail, then you'll leak the two successful allocations. I believe this should be if (!shut_txf_buf || !time_txf_buf || !hbeat_txf_buf) { printk(KERN_INFO "Unable to allocate memory for receive buffer\n"); kfree(hbeat_txf_buf); kfree(time_txf_buf); kfree(shut_txf_buf); return -ENOMEM; ... > + } > + > hv_cb_utils[HV_SHUTDOWN_MSG].channel->onchannel_callback = > &shutdown_onchannelcallback; > hv_cb_utils[HV_SHUTDOWN_MSG].callback = &shutdown_onchannelcallback; > @@ -298,6 +298,10 @@ static void exit_hyperv_utils(void) > hv_cb_utils[HV_HEARTBEAT_MSG].channel->onchannel_callback = > &chn_cb_negotiate; > hv_cb_utils[HV_HEARTBEAT_MSG].callback = &chn_cb_negotiate; > + > + kfree(shut_txf_buf); > + kfree(time_txf_buf); > + kfree(hbeat_txf_buf); > } > > module_init(init_hyperv_utils); > -- Jesper Juhl http://www.chaosbits.net/ Don't top-post http://www.catb.org/~esr/jargon/html/T/top-post.html Plain text mails only, please. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/