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[46.142.8.217]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-b84265abec6sm32761566b.14.2026.01.05.08.19.27 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 05 Jan 2026 08:19:28 -0800 (PST) Message-ID: Date: Mon, 5 Jan 2026 17:19:27 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2] net: sfp: add SMBus I2C block support Content-Language: en-US To: "Russell King (Oracle)" Cc: Andrew Lunn , Heiner Kallweit , "David S . Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, =?UTF-8?Q?Bj=C3=B8rn_Mork?= , Maxime Chevallier References: <20260105154653.575397-1-jelonek.jonas@gmail.com> From: Jonas Jelonek In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Hi Russell, On 05.01.26 17:16, Russell King (Oracle) wrote: > On Mon, Jan 05, 2026 at 03:46:53PM +0000, Jonas Jelonek wrote: >> @@ -765,26 +794,70 @@ static int sfp_smbus_byte_write(struct sfp *sfp, bool a2, u8 dev_addr, >> dev_addr++; >> } >> >> + return data - (u8 *)buf; > A separate fix is being submitted for this. > >> +} >> + >> +static int sfp_smbus_block_write(struct sfp *sfp, bool a2, u8 dev_addr, >> + void *buf, size_t len) >> +{ >> + size_t block_size = sfp->i2c_block_size; >> + union i2c_smbus_data smbus_data; >> + u8 bus_addr = a2 ? 0x51 : 0x50; >> + u8 *data = buf; >> + u8 this_len; >> + int ret; >> + >> + while (len) { >> + this_len = min(len, block_size); >> + >> + smbus_data.block[0] = this_len; >> + memcpy(&smbus_data.block[1], data, this_len); >> + ret = i2c_smbus_xfer(sfp->i2c, bus_addr, 0, >> + I2C_SMBUS_WRITE, dev_addr, >> + I2C_SMBUS_I2C_BLOCK_DATA, &smbus_data); >> + if (ret) >> + return ret; >> + >> + len -= this_len; >> + data += this_len; >> + dev_addr += this_len; >> + } >> + >> return 0; > This is wrong. As already said, the I2C accessors return the number of > bytes successfully transferred. Zero means no bytes were transferred, > which is an error. > > All callers to sfp_write() validate that the expected number of bytes > were written. Thus, returning zero will cause failures. > yes. I totally messed up v2 but already pushed out a v3 that fixes that, and has the separate fix as a prerequisite. Sorry for the confusion. Best, Jonas