From mboxrd@z Thu Jan 1 00:00:00 1970 From: Brian King Subject: Re: [PATCH 1/2] scsi: Add scsi_device max_cmd_len (resend) Date: Fri, 28 Apr 2006 16:43:18 -0500 Message-ID: <44528C76.2010006@us.ibm.com> References: <200604172240.k3HMes2V010154@d01av01.pok.ibm.com> <44522672.5010607@us.ibm.com> <1146237433.5251.7.camel@mulgrave.il.steeleye.com> <44525CBE.1030409@us.ibm.com> <1146249006.5251.64.camel@mulgrave.il.steeleye.com> <44526702.1010400@us.ibm.com> <1146257803.5251.82.camel@mulgrave.il.steeleye.com> <44528508.3060003@us.ibm.com> <445289F5.6070608@pobox.com> Reply-To: brking@us.ibm.com Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="------------040006040102080207070502" Return-path: In-Reply-To: <445289F5.6070608@pobox.com> Sender: linux-scsi-owner@vger.kernel.org To: Jeff Garzik Cc: James Bottomley , linux-scsi@vger.kernel.org, linux-ide@vger.kernel.org List-Id: linux-ide@vger.kernel.org This is a multi-part message in MIME format. --------------040006040102080207070502 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Jeff Garzik wrote: > Brian King wrote: >> Going along with that argument, there's really no good reason for >> libata to be playing games with scsi_host->max_cmd_len based on >> the attached devices. > > If both host controller and device support 16-byte CDB, it should not be > limited to 12 bytes. Agreed. > libata is not "playing games", just exporting what the hardware supports > as best the API allows. It needs to support 16-byte CDBs for the same > reason any SCSI LLDD supports 16-byte CDBs. > > Remember ATAPI<->SCSI bridges exist, thus any SCSI disk can appear > attached to ATAPI. The libata code in question is the code that changes scsi_host->max_cmd_len based on what the attached devices support. I propose the following patch. This patch is untested. -- Brian King eServer Storage I/O IBM Linux Technology Center --------------040006040102080207070502 Content-Type: text/x-patch; name="libata_max_cmd_len.patch" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="libata_max_cmd_len.patch" CgpTaWduZWQtb2ZmLWJ5OiBCcmlhbiBLaW5nIDxicmtpbmdAdXMuaWJtLmNvbT4KLS0tCgog bGliYXRhLWRldi1iamtpbmcxL2RyaXZlcnMvc2NzaS9saWJhdGEtY29yZS5jIHwgICAgOCAr LS0tLS0tLQogMSBmaWxlcyBjaGFuZ2VkLCAxIGluc2VydGlvbigrKSwgNyBkZWxldGlvbnMo LSkKCmRpZmYgLXB1TiBkcml2ZXJzL3Njc2kvbGliYXRhLWNvcmUuY35saWJhdGFfbWF4X2Nt ZF9sZW4gZHJpdmVycy9zY3NpL2xpYmF0YS1jb3JlLmMKLS0tIGxpYmF0YS1kZXYvZHJpdmVy cy9zY3NpL2xpYmF0YS1jb3JlLmN+bGliYXRhX21heF9jbWRfbGVuCTIwMDYtMDQtMjggMTY6 MzQ6MTYuMDAwMDAwMDAwIC0wNTAwCisrKyBsaWJhdGEtZGV2LWJqa2luZzEvZHJpdmVycy9z Y3NpL2xpYmF0YS1jb3JlLmMJMjAwNi0wNC0yOCAxNjozNDo0MC4wMDAwMDAwMDAgLTA1MDAK QEAgLTEzMjgsMTIgKzEzMjgsNiBAQCBzdGF0aWMgaW50IGF0YV9kZXZfY29uZmlndXJlKHN0 cnVjdCBhdGFfCiAJCQkgICAgICAgYXAtPmlkLCBkZXYtPmRldm5vLCBhdGFfbW9kZV9zdHJp bmcoeGZlcl9tYXNrKSk7CiAJfQogCi0JYXAtPmhvc3QtPm1heF9jbWRfbGVuID0gMDsKLQlm b3IgKGkgPSAwOyBpIDwgQVRBX01BWF9ERVZJQ0VTOyBpKyspCi0JCWFwLT5ob3N0LT5tYXhf Y21kX2xlbiA9IG1heF90KHVuc2lnbmVkIGludCwKLQkJCQkJICAgICAgYXAtPmhvc3QtPm1h eF9jbWRfbGVuLAotCQkJCQkgICAgICBhcC0+ZGV2aWNlW2ldLmNkYl9sZW4pOwotCiAJLyog bGltaXQgYnJpZGdlIHRyYW5zZmVycyB0byB1ZG1hNSwgMjAwIHNlY3RvcnMgKi8KIAlpZiAo YXRhX2Rldl9rbm9iYmxlKGFwLCBkZXYpKSB7CiAJCWlmIChwcmludF9pbmZvKQpAQCAtNDU3 Myw3ICs0NTY3LDcgQEAgc3RhdGljIHZvaWQgYXRhX2hvc3RfaW5pdChzdHJ1Y3QgYXRhX3Bv cgogCWhvc3QtPm1heF9sdW4gPSAxOwogCWhvc3QtPm1heF9jaGFubmVsID0gMTsKIAlob3N0 LT51bmlxdWVfaWQgPSBhdGFfdW5pcXVlX2lkKys7Ci0JaG9zdC0+bWF4X2NtZF9sZW4gPSAx MjsKKwlob3N0LT5tYXhfY21kX2xlbiA9IEFUQVBJX0NEQl9MRU47CiAKIAlhcC0+ZmxhZ3Mg PSBBVEFfRkxBR19ESVNBQkxFRDsKIAlhcC0+aWQgPSBob3N0LT51bmlxdWVfaWQ7Cl8K --------------040006040102080207070502--